顔写真

マツモト ユウジ
松本 祐司
Yuji Matsumoto
所属
大学院工学研究科 応用化学専攻 原子・分子制御工学講座
職名
教授
学位
  • 博士(理学)(東京大学)

  • 修士(理学)(東京大学)

経歴 6

  • 2013年4月 ~ 継続中
    東北大学大学院 工学研究科 教授

  • 2007年4月 ~ 2013年3月
    東京工業大学 応用セラミックス研究所 セラミックス機能部門 応用セラミックス研究所 セラミックス機能部門 准教授

  • 1996年 ~ 1997年
    :Japan Sociery for the Promotion of Science Research Fellowships for Research Fellowships

  • 1996年 ~ 1997年
    :日本学術振興会 特別研究員

  • 1998年 ~
    -:東京工業大学 助手

  • 1998年 ~
    -:Tokyo Institute of Technology Research Associate

︎全件表示 ︎最初の5件までを表示

学歴 3

  • 東京大学大学院 理学系研究科 化学

    ~ 1998年

  • 東京大学

    ~ 1998年

  • 東京大学 理学部 化学

    ~ 1993年

所属学協会 5

  • 日本化学会

  • 日本フラックス成長研究会

  • イオン液体研究会

  • 応用物理学会

  • 日本表面真空学会

研究キーワード 8

  • SiC

  • イオン液体

  • 有機半導体

  • 酸化物

  • 電気化学

  • 真空プロセス

  • 結晶成長

  • 薄膜

研究分野 3

  • ナノテク・材料 / 無機材料、物性 /

  • ナノテク・材料 / 薄膜、表面界面物性 /

  • ナノテク・材料 / 機能物性化学 /

受賞 3

  1. 文部科学大臣表彰 科学技術賞(研究部門)

    2008年

  2. 第24回(2008年春季)応用物理学会講演奨励賞

    2008年

  3. 東工大挑戦的研究賞

    2008年

論文 262

  1. Combinatorial characterization of metastable luminous silver cations 査読有り

    Hirokazu Masai, Masanori Koshimizu, Hiroki Kawamoto, Hiroyuki Setoyama, Yohei Onodera, Kazutaka Ikeda, Shingo Maruyama, Naoki Haruta, Tohru Sato, Yuji Matsumoto, Chika Takahashi, Teruyasu Mizoguchi

    Scientific Reports 14 (1) 4638 2024年2月26日

    出版者・発行元:Springer Science and Business Media LLC

    DOI: 10.1038/s41598-024-55014-8  

    ISSN:0021-4922

    eISSN:2045-2322

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    Abstract Thermodynamically metastable glasses that can contain metastable species are important functional materials. X-ray absorption near-edge structure (XANES) spectroscopy is an effective technique for determining the valence states of cations, especially for the doping element in phosphors. Herein, we first confirm the valence change of silver cations from monovalent to trivalent in aluminophosphate glasses by X-ray irradiation using a combination of Ag L<sub>3</sub>-edge XANES, electron spin resonance, and simulated XANES spectra based on first-principles calculations. The absorption edge of the experimental and simulated XANES spectra demonstrate the spectral features of Ag(III), confirming that AgO exists as Ag(I)Ag(III)O<sub>2</sub>. A part of Ag(I) changes to Ag(III) by X-ray irradiation, and the generation of Ag(III) is saturated after high irradiation doses, in good agreement with conventional radiophotoluminescence (RPL) behaviour. The structural modelling based on a combination of quantum beam analysis suggests that the local coordination of Ag cations is similar to that of Ag(III), which is confirmed by density functional theory calculations. This demonstration of Ag(III) in glass overturns the conventional understanding of the RPL mechanism of silver cations, redefining the science of silver-related materials.

  2. Epitaxial growth of copper phthalocyanine on a large single-grain of thin film alkyl perylene diimide 査読有り

    Shuhei Tanaka, Yusuke Takagawa, Shingo Maruyama, Yosei Shibata, Tomoyuki Koganezawa, Kenichi Kaminaga, Hideo Fujikake, Yuji Matsumoto

    Japanese Journal of Applied Physics 63 (2) 025502-025502 2024年2月6日

    出版者・発行元:IOP Publishing

    DOI: 10.35848/1347-4065/ad1847  

    ISSN:0021-4922

    eISSN:1347-4065

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    Abstract In this work, heteroepitaxial growth of copper phthalocyanine (CuPc) on a large single-grain of thin film N,N’-Di-n-octyl-3,4,9,10-perylenetetracarboxylic diimide (PTCDI-C8) was investigated. Vacuum-deposited PTCDI-C8 thin films at a growth temperature of ∼180 °C exhibited large grain growth of several hundred micrometers or more in size, and their surface consisted of stripe islands with molecular steps. CuPc deposited at 180 °C on this PTCDI-C8 large grain underlayer was found to grow epitaxially with its needle-like crystals dominantly oriented in one unique direction. The mechanism of the observed epitaxy is discussed based on the results of in-plane X-ray diffraction and the initial growth morphology.

  3. Infrared laser deposition of high-quality CsBH<sub>4</sub> epitaxial thin films stable under atmospheric conditions 査読有り

    Hibiki Murakami, Kenichi Kaminaga, Rintaro Kimura, Shingo Maruyama, Yuji Matsumoto

    Japanese Journal of Applied Physics 63 020905 2024年2月5日

    出版者・発行元:IOP Publishing

    DOI: 10.35848/1347-4065/ad2623  

    ISSN:0021-4922

    eISSN:1347-4065

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    Abstract We have demonstrated the growth of CsBH<sub>4</sub> (001) epitaxial thin films utilizing an infrared laser deposition technique. The thin film exhibited the coherent growth with a tensile strain from the substrate, resulting in its crystallinity superior to other kinds of metal borohydride thin films reported in earlier studies. Moreover, the notable chemical stability of CsBH<sub>4</sub> enabled surface morphological and optical characterizations even under atmospheric conditions, which is a challenge to other metal borohydride thin films. The optical transition energy values estimated from a Tauc plot were found smaller than the theoretical ones previously reported, and DFT calculations suggested a partial deficiency of Cs<sup>+</sup> or [BH<sub>4</sub>]<sup>−</sup> created in the thin films.

  4. NaCl flux growth of non-polar m-plane ZnO epitaxial thin film on c-plane sapphire substrate 査読有り

    Kouki Kuroda, Kenichi Kaminaga, Takuto Tobe, Shingo Maruyama, Yuji Matsumoto

    Thin Solid Films 788 140169-140169 2023年12月9日

    出版者・発行元:None

    DOI: 10.1016/j.tsf.2023.140169  

    ISSN:0040-6090

  5. Ferroelectric Organic Semiconductor: [1]Benzothieno[3,2-<i>b</i>][1]benzothiophene-Bearing Hydrogen-Bonding −CONHC<sub>14</sub>H<sub>29</sub> Chain 査読有り

    Kohei Sambe, Takashi Takeda, Norihisa Hoshino, Wakana Matsuda, Riku Miura, Kanae Tsujita, Shingo Maruyama, Shunsuke Yamamoto, Shu Seki, Yuji Matsumoto, Tomoyuki Akutagawa

    ACS Applied Materials &amp; Interfaces 15 (50) 58711-58722 2023年12月6日

    出版者・発行元:American Chemical Society (ACS)

    DOI: 10.1021/acsami.3c14476  

    ISSN:1944-8244

    eISSN:1944-8252

  6. Ionic Liquid Crystal Thin Film as Switching Layer in Nonvolatile Resistive Memory 査読有り

    Wenzhong Zhang, Haruka Komatsu, Shingo Maruyama, Kenichi Kaminaga, Yuji Matsumoto

    ACS Applied Materials &amp; Interfaces 15 52806-52813 2023年11月1日

    出版者・発行元:American Chemical Society (ACS)

    DOI: 10.1021/acsami.3c13980  

    ISSN:1944-8244

    eISSN:1944-8252

  7. Reaction Dynamics of C(NH<sub>2</sub>)<sub>3</sub>SnI<sub>3</sub> Formation from Vacuum-Deposited C(NH<sub>2</sub>)<sub>3</sub>I and SnI<sub>2</sub> Bilayer Thin Films Investigated by <i>In Situ</i> Infrared Multiple-Angle Incidence-Resolved Spectroscopy 査読有り

    Kazuki Shimada, Shingo Maruyama, Tetsuhiko Miyadera, Kenichi Kaminaga, Yuji Matsumoto

    ACS Applied Materials &amp; Interfaces 15 45411-45417 2023年9月14日

    出版者・発行元:American Chemical Society (ACS)

    DOI: 10.1021/acsami.3c08708  

    ISSN:1944-8244

    eISSN:1944-8252

  8. Ionic Liquid-Assisted Vacuum Deposition of Organic Ionic Plastic Crystal Thin Films

    Yota Matsuoka, Shingo Maruyama, Kenichi Kaminaga, Yuji Matsumoto

    ECS Journal of Solid State Science and Technology 12 (7) 074006-074006 2023年7月1日

    出版者・発行元:The Electrochemical Society

    DOI: 10.1149/2162-8777/ace797  

    ISSN:2162-8769

    eISSN:2162-8777

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    We report the preparation of thin films of 1-ethyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)amide ([C<sub>2</sub>mpyr][TFSA]), which is among organic ionic plastic crystals, using an ionic liquid (IL) -assisted vacuum deposition method. 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide ([C<sub>2</sub>mim][TFSA]), a well-known IL, was used as a solvent to assist the crystal growth. The effect of the IL on the growth morphology and crystal orientation of the thin films was investigated. It was found that the IL-assisted growth resulted in the preferential growth of (100)-oriented [C<sub>2</sub>mpyr][TFSA] crystallites, whose morphology depended on the deposition temperature and the presence of IL. Growth models for [C<sub>2</sub>mpyr][TFSA] thin films under different growth conditions are proposed and discussed.

  9. Near-Ultraviolet Light-Driven Photocathodic Activity for (001)-Oriented BiOCl Thin Films Synthesized by Mist Chemical Vapor Deposition

    Zaichun Sun, Shaoyong Qin, Daichi Oka, Huijuan Zhang, Tomoteru Fukumura, Yuji Matsumoto, Bingchu Mei

    Inorganic Chemistry 62 (23) 8914-8922 2023年5月31日

    出版者・発行元:American Chemical Society (ACS)

    DOI: 10.1021/acs.inorgchem.3c00466  

    ISSN:0020-1669

    eISSN:1520-510X

  10. 液晶相を経由した結晶化プロセスによる高品質な真空蒸着有機結晶薄膜の作製

    丸山 伸伍, 小松 陽花, 辻田 香奈瑛, 神永 健一, 松本 祐司

    66 (4) 209-214 2023年4月10日

    出版者・発行元:None

    DOI: 10.1380/vss.66.209  

    ISSN:2433-5835

    eISSN:2433-5843

  11. Giant Grain Growth of 2,5-Di(2-thienyl)-1<i>H</i>-pyrrole Crystal Films: Kinetic Analysis of Self-Crystallization from Its Supercooled Liquid in Vacuum Deposition

    Keiichiro Seta, Shingo Maruyama, Tomoyuki Koganezawa, Kenichi Kaminaga, Yuji Matsumoto

    Crystal Growth &amp; Design 23 (5) 3731-3739 2023年4月3日

    出版者・発行元:American Chemical Society (ACS)

    DOI: 10.1021/acs.cgd.3c00128  

    ISSN:1528-7483

    eISSN:1528-7505

  12. 真空電気化学アプローチによる酸化物-イオン液体界面の研究

    松本 祐司

    66 (3) 176-181 2023年3月10日

    出版者・発行元:None

    DOI: 10.1380/vss.66.176  

    ISSN:2433-5835

    eISSN:2433-5843

  13. Recent Progress in Vacuum Engineering of Ionic Liquids 査読有り

    Yuji Matsumoto

    Molecules 28 (4) 1991-1991 2023年2月20日

    出版者・発行元:MDPI AG

    DOI: 10.3390/molecules28041991  

    eISSN:1420-3049

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    Since the discovery of ionic liquids (ILs) as a new class of liquid that can survive in a vacuum at room temperature, they have been aimed at being characterized with vacuum analysis techniques and used in vacuum processes for the last two decades. In this review, our state-of-the-art of the vacuum engineering of ILs will be introduced. Beginning with nanoscale vacuum deposition of IL films and their thickness-dependent ionic conductivity, there are presented some new applications of the ellipsometry to in situ monitoring of the thickness of IL films and their glass transitions, and of the surface thermal fluctuation spectroscopy to investigation of the rheological properties of IL films. Furthermore, IL-VLS (vapor-liquid-solid) growth, a vacuum deposition via IL, has been found successful, enhancing the crystallinity of vacuum-deposited crystals and films, and sometimes controlling their surface morphology and polymorphs. Among recent applications of ILs are the use of metal ions-containing IL and thin film nano IL gel. The former is proposed as a low temperature evaporation source of metals, such as Ta, in vacuum deposition, while the latter is demonstrated to work as a gate electrolyte in an electric double layer organic transistor.

  14. Directional lateral crystallization of vacuum-deposited C8-BTBT thin films <i>via</i> liquid crystal phase by a seeded horizontal temperature gradient cooling technique

    Kanae Tsujita, Shingo Maruyama, Yosesi Shibata, Tomoyuki Koganezawa, Kenichi Kaminaga, Hideo Fujikake, Yuji Matsumoto

    CrystEngComm 25 (1) 64-71 2023年

    出版者・発行元:Royal Society of Chemistry (RSC)

    DOI: 10.1039/d2ce01280d  

    eISSN:1466-8033

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    C8-BTBT thin films with large domain sizes were grown by vacuum deposition and subsequent post-annealing and cooling crystallization via liquid crystal phase with a constant horizontal temperature gradient.

  15. Direct visualization of high-temperature dissolution dynamics of α-Al2O3(0 0 0 1) with an oxide-based melt flux of Sn:BiOx

    Yuri Ishizaki, Kenichi Kaminaga, Shingo Maruyama, Yuji Matsumoto

    Chemical Physics Letters 803 139869-139869 2022年9月

    出版者・発行元:Elsevier BV

    DOI: 10.1016/j.cplett.2022.139869  

    ISSN:0009-2614

  16. Surface charge dependent structure of ionic liquid/alkali halide interfaces investigated by atomic force microscopy 査読有り

    Harshal P. Mungse, Saki Okudaira, Miho Yamauchi, Takashi Ichii, Toru Utsunomiya, Shingo Maruyama, Yuji Matsumoto, Hiroyuki Sugimura

    Japanese Journal of Applied Physics 61 (SL) SL1009-SL1009 2022年9月1日

    出版者・発行元:IOP Publishing

    DOI: 10.35848/1347-4065/ac528e  

    ISSN:0021-4922

    eISSN:1347-4065

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    Abstract Ionic liquid (IL)/solid interfaces are relevant to a broad range of physicochemical phenomena and technological processes such as catalysis, corrosion, electrochemistry, and lubrication. Hence, understanding the effect of substrate surface nature on the interfacial properties has a significant impact on improving technological processes in which interfacial properties are dominant. In this work, we investigated interfacial structures between 1-butyl-3-methylimidazolium hexafluorophosphate (BMI-PF<sub>6</sub>) IL and KBr crystal surfaces by frequency modulation atomic force microscopy utilizing a quartz tuning fork sensor. KBr(100) and (111) surfaces were used as the substrates, where the (100) surface is electrically neutral, and the (111) surface is highly charged. We investigated the influence of surface charge on their surface structures and interfacial solvation structures by atomic-scale topographic imaging and frequency shift versus distance curve measurement. The behavior of IL at these two interfaces was found to be significantly different due to these different surface properties.

  17. Electric Double Layer Action of High-quality Ionic Liquid Crystal Thin Films 査読有り

    Haruka Komatsu, Miyuki Tanaka, Kenichi Kaminaga, Shingo Maruyama, Yuji Matsumoto

    Chemistry Letters 51 (2) 162-165 2022年2月5日

    出版者・発行元:The Chemical Society of Japan

    DOI: 10.1246/cl.210692  

    ISSN:0366-7022

    eISSN:1348-0715

  18. Direct visualization of kinetic reversibility of crystallization and dissolution behavior at solution growth interface of SiC in Si-Cr solvent 査読有り

    Kota Nakano, Shingo Maruyama, Tomohisa Kato, Yoshiyuki Yonezawa, Hajime Okumura, Yuji Matsumoto

    Surfaces and Interfaces 28 101664-101664 2022年2月

    出版者・発行元:Elsevier BV

    DOI: 10.1016/j.surfin.2021.101664  

    ISSN:2468-0230

  19. Impact of band-gap graded structures artificially implemented in Mg–ZnO epitaxial films on photoelectrochemical properties

    Yuta Sato, Kenichi Kaminaga, Ryota Takahashi, Shingo Maruyama, Yuji Matsumoto

    Catalysis Science &amp; Technology 2022年

    出版者・発行元:Royal Society of Chemistry (RSC)

    DOI: 10.1039/d2cy01178f  

    ISSN:2044-4753

    eISSN:2044-4761

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    The impact of band gap-graded structures artificially implemented in a photocatalyst on the photoelectrochemical properties was investigated in a model system of epitaxial thin film Mg–ZnO.

  20. Compositionally graded crystals as a revived approach for new crystal engineering for the exploration of novel functionalities 査読有り

    Yuji Matsumoto, Shingo Maruyama, Kenichi Kaminaga

    CrystEngComm 24 (13) 2359-2369 2022年

    出版者・発行元:Royal Society of Chemistry (RSC)

    DOI: 10.1039/d2ce00041e  

    eISSN:1466-8033

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    Nanoscale compositionally graded crystals have huge potential to allow the exploration of new functionalities through crystal lattice modulation.

  21. Room-Temperature Preparation of Ta Ions-Containing Ionic Liquid and its Vapor Deposition toward Ta-Oxide Film Coating 査読有り

    Nana Hozuki, Kenichi Kaminaga, Shingo Maruyama, Daisuke Shiga, Hiroshi Kumigashira, Hidetaka Takato, Michio Kondo, Yuji Matsumoto

    Journal of The Electrochemical Society 169 (1) 013504-013504 2022年1月1日

    出版者・発行元:The Electrochemical Society

    DOI: 10.1149/1945-7111/ac48c5  

    ISSN:0013-4651

    eISSN:1945-7111

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    Ta ions-containing solutions, which are brown in color with no precipitation, were successfully prepared through an electroelution process with ionic liquid (IL). An as-delivered Ta metal plate covered with a passivation oxide film could be easily eluted even at room temperature by simply applying an anodic potential of, e.g. +2.2 V vs Ag in [Bmim][PF<sub>6</sub>] IL. According to the quantity of electric charge required for oxidation of Ta, most Ta ions in the IL were suggested to be in an oxidation state of +5, which was also confirmed by X-ray photoemission spectroscopy (XPS). Ta ions in IL were found to thermally evaporate together with IL molecules by heating in a vacuum, forming a deposit of the Ta ions-containing IL on a substrate. The Ta concentrations in the deposits were reduced uniquely by about one order of magnitude from those in the original bulk source through the evaporation process under the present conditions. Furthermore, a possibility of the formation of thin film-like Ta oxide from such a Ta ions-containing IL deposit and its bulk droplet prepared on substrates by annealing in air at 1000 °C will be discussed.

  22. Epitaxial pillar–matrix nanocomposite thin films of Bi–Ti–Fe–O and CoFe2O4 grown on SrTiO3 (110)

    Y. Kawahira, R. Harada, S. Maruyama, T. Koganezawa, S. Yasui, M. Itoh, Y. Matsumoto

    Journal of Applied Physics 130 (8) 084101-084101 2021年8月28日

    出版者・発行元:AIP Publishing

    DOI: 10.1063/5.0060610  

    ISSN:0021-8979

    eISSN:1089-7550

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    Controlling nanostructures and crystallographic orientations in epitaxial nanocomposite thin films are important for tuning their physical properties. Here, we present epitaxial nanocomposite thin films of (110) oriented CoFe2O4 (CFO) and (11-10) oriented Bi5Ti3FeO15 (BTFO15) grown on SrTiO3 (110) substrates with a vertically aligned pillar-matrix type structure. The size and density of CFO pillars embedded in the BTFO matrix were controlled by the growth temperature and CFO concentration. Moreover, BTFO takes intergrowth phases with the general formula of Bi4Ti3O12•nBiFeO3 (n=1-∼1.5) depending on the growth temperature. Scanning probe analysis on the ferroelectric properties of BTFO15-CFO nanocomposite thin films suggested that the BTFO has a switchable out-of-plane polarization component originating from the tilted orientation of its a-b plane polarization. For high CFO pillar density, however, a non-negligible number of conductive paths which might be formed at the pillar-matrix interface are likely to prevent the polarization reversal.

  23. Polarization characteristics of single-crystalline dichroic azo dye grown in nematic-phase liquid crystal 査読有り

    Yosei Shibata, Shingo Maruyama, Takahiro Ishinabe, Yuji Matsumoto, Hideo Fujikake

    Japanese Journal of Applied Physics 60 (8) 081001-081001 2021年8月1日

    出版者・発行元:IOP Publishing

    DOI: 10.35848/1347-4065/ac1389  

    ISSN:0021-4922

    eISSN:1347-4065

  24. Surface thermal fluctuation spectroscopy study of ultra-thin ionic liquid films on quartz 査読有り

    Shingo Maruyama, Yuki Ishikawa, Takahisa Mitsui, Kenichiro Aoki, Yuji Matsumoto

    Applied Physics Express 14 (7) 075503-075503 2021年7月1日

    出版者・発行元:IOP Publishing

    DOI: 10.35848/1882-0786/ac08d1  

    ISSN:1882-0778

    eISSN:1882-0786

  25. Artificially Designed Compositionally Graded Sr-Doped NaTaO3 Single-Crystalline Thin Films and the Dynamics of Their Photoexcited Electron–Hole Pairs 査読有り

    Rio Konno, Shingo Maruyama, Takumu Kosaka, Ryuzi Katoh, Ryota Takahashi, Hiroshi Kumigashira, Nobuyuki Ichikuni, Hiroshi Onishi, Yuji Matsumoto

    Chemistry of Materials 33 (1) 226-233 2021年1月12日

    出版者・発行元:American Chemical Society (ACS)

    DOI: 10.1021/acs.chemmater.0c03487  

    ISSN:0897-4756

    eISSN:1520-5002

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    Sr-doped NaTaO3 (NTO) single-crystalline films with different Sr compositions of up to 20 mol %, including an NTO film, were first fabricated on LaAlO3(001) substrates by pulsed laser deposition. A gradual simultaneous increase of the lattice constants and the optical absorption edge energy was found as the doped Sr composition increased, seemingly exhibiting a structural discontinuity at a critical doping level of around 10 mol %. Extended X-ray absorption fine structure (EXAFS) analysis revealed that the doped Sr atoms were substituted for both the A and B sites, with their stoichiometric number ratio close to that previously reported for bulk Sr-doped NTO samples, resulting in the Sr-doped NTO films being still highly insulative comparable to the NTO film. Second, in spite of the well-known intrinsic nature of the high diffusivity of Sr ions in oxides, the compositionally graded Sr-doped NTO films were successfully fabricated almost as designed to have the upward and downward Sr composition gradients with a maximum doping level of 10 mol % from the substrate along the growth direction within the films. The preliminary time-resolved microwave conductivity measurement demonstrated that the lifetime of the photoexcited carriers in the compositionally graded Sr-doped NTO films was longer than in any of the NTO and homogeneous Sr-doped NTO films.

  26. Sequential variation of super periodic structures emerged in Bi-layered perovskite pillar-matrix epitaxial nanocomposite films with spinel ferrites 査読有り

    R. Harada, Y. Kawahira, T. Ikeda, S. Maruyama, Y. Matsumoto

    CrystEngComm 23 (47) 8404-8410 2021年

    出版者・発行元:Royal Society of Chemistry (RSC)

    DOI: 10.1039/d1ce00990g  

    eISSN:1466-8033

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    The phase stability of Aurivillius bismuth-layer structured Bi<sub>5</sub>Ti<sub>3</sub>FeO<sub>15</sub> (BTFO15) has been investigated in an epitaxial pillar-matrix nanocomposite system with spinel ferrites.

  27. Vapor–liquid–solid growth of 4H-SiC single crystal films with extremely low carrier densities in chemical vapor deposition with a Pt–Si alloy flux and X-ray topography analysis of their dislocation propagation behaviors

    Naoki Sanoodo, Tomohisa Kato, Yoshiyuki Yonezawa, Kazutoshi Kojima, Yuji Matsumoto

    CrystEngComm 23 (29) 5039-5044 2021年

    出版者・発行元:Royal Society of Chemistry (RSC)

    DOI: 10.1039/d1ce00625h  

    eISSN:1466-8033

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    <p>The CVD–VLS process for 4H-SiC films with a Pt–Si alloy flux achieved their low carrier densities of ∼10<sup>15</sup> cm<sup>−3</sup>, demonstrating a remarkable etch back effect and a possible conversion of TEDs and TSDs in the substrate to BPDs in the films.</p>

  28. Vapour-liquid-solid-like growth of high-quality and uniform 3C-SiC heteroepitaxial films on α-Al2O3(0001) substrates 査読有り

    Naoki Sannodo, Asuka Osumi, Kenichi Kaminaga, Shingo Maruyama, Y. Matsumoto

    CrystEngComm 23 (8) 1709-1717 2021年

    出版者・発行元:Royal Society of Chemistry (RSC)

    DOI: 10.1039/d0ce01793k  

    eISSN:1466-8033

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    <p>We demonstrate a heteroepitaxial growth of 3C-SiC thin films on α-Al<sub>2</sub>O<sub>3</sub>(0001) substrates by a vapour-liquid-solid (VLS)-like mechanism, an advanced process of alternating deposition of SiC and NiSi<sub>2</sub> flux in nanoscale,...</p>

  29. A New Route to Carbon Film Coating by Anodic Electrodeposition from Ionic Liquid Containing Different Phenylsilane Derivatives 査読有り

    Nana Hozuki, Hidetaka Takato, Shingo Maruyama, Michio Kondo, Kenjiro Fujimoto, Yuji Matsumoto

    Chemistry Letters 49 (11) 1349-1352 2020年11月5日

    出版者・発行元:The Chemical Society of Japan

    DOI: 10.1246/cl.200537  

    ISSN:0366-7022

    eISSN:1348-0715

  30. Flux-Mediated Doping of Bi into (La,Sr)MnO3 Films Grown on NdGdO3 (110) Substrates 査読有り

    Koji Mizufune, Hiroshi Naganuma, Shingo Maruyama, Yuji Matsumoto

    ACS Applied Electronic Materials 2020年10月28日

    出版者・発行元:American Chemical Society (ACS)

    DOI: 10.1021/acsaelm.0c00718  

    ISSN:2637-6113

    eISSN:2637-6113

  31. Nanogels Constituted of Polyurea Filled with an Ionic Liquid as an Electrolyte for Electric Double-Layer Transistors 査読有り

    Hikaru Watanabe, Ryoji Takazawa, Rikuto Takahashi, Shingo Maruyama, Yuji Matsumoto

    ACS Applied Nano Materials 3 (10) 9610-9615 2020年10月23日

    出版者・発行元:American Chemical Society (ACS)

    DOI: 10.1021/acsanm.0c02335  

    ISSN:2574-0970

    eISSN:2574-0970

  32. In situ vacuum ellipsometry approach to investigation of glass transition behavior in ionic liquid thin films 査読有り

    Yuki Ishikawa, Shingo Maruyama, Yuji Matsumoto

    Chemical Physics Letters 754 137691-137691 2020年9月

    出版者・発行元:Elsevier BV

    DOI: 10.1016/j.cplett.2020.137691  

    ISSN:0009-2614

  33. Vacuum Electrochemistry Approach to Investigate Electrical Double‐Layer Capacitances of Ionic Liquid for Epitaxial Thin‐Film Electrodes of TiO₂ and SrO on Niobium‐Doped (001)SrTiO₃ 査読有り

    Chika Takahashi, Mariko Kanai, Shingo Maruyama, Yuji Matsumoto

    ChemElectroChem 7 (15) 3253-3259 2020年8月3日

    出版者・発行元:Wiley

    DOI: 10.1002/celc.202000620  

    ISSN:2196-0216

    eISSN:2196-0216

  34. In situ diagnosis of vacuum-deposited nanoscale ionic liquid [emim][TFSA], Li salt [Li][TFSA] and their solution films through a combination of ellipsometry and impedance spectroscopy 査読有り

    Ryoji Takazawa, Kaho Toyabe, Shingo Maruyama, Yuji Matsumoto

    Japanese Journal of Applied Physics 59 (8) 085001-085001 2020年8月1日

    出版者・発行元:IOP Publishing

    DOI: 10.35848/1347-4065/aba6cd  

    ISSN:0021-4922

    eISSN:1347-4065

  35. High-Throughput and Autonomous Grazing Incidence X-ray Diffraction Mapping of Organic Combinatorial Thin-Film Library Driven by Machine Learning 査読有り

    Shingo Maruyama, Kana Ouchi, Tomoyuki Koganezawa, Yuji Matsumoto

    ACS Combinatorial Science 22 (7) 348-355 2020年7月13日

    出版者・発行元:American Chemical Society (ACS)

    DOI: 10.1021/acscombsci.0c00037  

    ISSN:2156-8952

    eISSN:2156-8944

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    © 2020 American Chemical Society. High-throughput X-ray diffraction (XRD) is one of the most indispensable techniques to accelerate materials research. However, the conventional XRD analysis with a large beam spot size may not best appropriate in a case for characterizing organic materials thin film libraries, in which various films prepared under different process conditions are integrated on a single substrate. Here, we demonstrate that high-resolution grazing incident XRD mapping analysis is useful for this purpose: A 2-dimensional organic combinatorial thin film library with the composition and growth temperature varied along the two orthogonal axes was successfully analyzed by using synchrotron microbeam X-ray. Moreover, we show that the time-consuming mapping process is accelerated with the aid of a machine learning technique termed as Bayesian optimization based on Gaussian process regression.

  36. Vapor-liquid-solid-like growth of thin film SiC by nanoscale alternating deposition of SiC and NiSi₂ 査読有り

    Naoki Sannodo, Asuka Osumi, Shingo Maruyama, Yuji Matsumoto

    Applied Surface Science 530 2020年7月

  37. Platinum additive impacts on vapor-liquid-solid growth chemical interface for high-quality SiC single crystal films 査読有り

    A. Osumi, K. Nakano, N. Sannodo, S. Maruyama, Y. Matsumoto, T. Mitani, T. Kato, Y. Yonezawa, H. Okumura

    Materials Today Chemistry 16 100266-100266 2020年6月

    出版者・発行元:Elsevier BV

    DOI: 10.1016/j.mtchem.2020.100266  

    ISSN:2468-5194

  38. In-vacuum electropolymerization of vapor-deposited source molecules into polymer films in ionic liquid 査読有り

    Keisuke Okawara, Tomonobu Nishimura, Shingo Maruyama, Masaki Kubo, Yuji Matsumoto

    Reaction Chemistry & Engineering 5 (1) 33-38 2020年

    出版者・発行元:Royal Society of Chemistry (RSC)

    DOI: 10.1039/c9re00343f  

    eISSN:2058-9883

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    <p>A new in-vacuum electropolymerization process combined with vapor-phase deposition using an ionic liquid (IL) has been proposed.</p>

  39. Ionic liquid wettability of CVD-grown graphene on Cu/α-Al2O3(0 0 0 1) characterized by in situ contact angle measurement in a vacuum 査読有り

    Takuya Kinoshita, Shingo Maruyama, Yuji Matsumoto

    Chemical Physics Letters 735 136781-136781 2019年11月

    出版者・発行元:Elsevier BV

    DOI: 10.1016/j.cplett.2019.136781  

    ISSN:0009-2614

  40. Pulsed laser deposition with rapid beam deflection by a galvanometer mirror scanner 査読有り

    S. Maruyama, N. Sannodo, R. Harada, Y. Anada, R. Takahashi, M. Lippmaa, Y. Matsumoto

    Review of Scientific Instruments 90 (9) 093901-093901 2019年9月

    出版者・発行元:AIP Publishing

    DOI: 10.1063/1.5104291  

    ISSN:0034-6748

    eISSN:1089-7623

  41. Epitaxial Film Growth of LiBH₄ via Molecular Unit Evaporation 査読有り

    Hiroyuki Oguchi, Sangryun Kim, Shingo Maruyama, Yuhei Horisawa, Shigeyuki Takagi, Toyoto Sato, Ryota Shimizu, Yuji Matsumoto, Taro Hitosugi, Shin-ichi Orimo

    Electronic Materials 1 (9) 1792-1796 2019年8月16日

    出版者・発行元:None

    DOI: 10.1021/acsaelm.9b00350  

    ISSN:2637-6113

  42. Ionic liquid-assisted vapor deposition and polymorphs control of 2,2′:5′,2″-terthiophene crystals 査読有り

    Keisuke Okawara, Shingo Maruyama, Yuji Matsumoto

    Japanese Journal of Applied Physics 58 (8) 085503-1-085503-5 2019年7月

    DOI: 10.7567/1347-4065/ab3067  

  43. Fabrication of ionic liquid polycrystalline nano thin films and their ion conducting properties accompanied by solid-liquid phase transition 査読有り

    Aya Yoshii, Shingo Maruyama, Kaho Toyabe, Ryoji Takazawa, Tomoyuki Koganezawa, Yuji Matsumoto

    Thin Solid Films 677 77-82 2019年5月

    DOI: 10.1016/j.tsf.2019.03.017  

  44. Ionic liquid/ZnO(0001̄) single crystal and epitaxial film interfaces studied through a combination of electrochemical measurements and a pulsed laser deposition process under vacuum 査読有り

    Mariko Kanai, Ko Watanabe, Shingo Maruyama, Yuji Matsumoto

    Physical Chemistry Chemical Physics 21 (45) 25506-25512 2019年

    出版者・発行元:Royal Society of Chemistry (RSC)

    DOI: 10.1039/c9cp04875h  

    ISSN:1463-9076

    eISSN:1463-9084

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    <p>O-Polar ZnO(0001̄) single crystals and ZnO and Mg-doped ZnO films which were subsequently deposited on the ZnO crystals by pulsed laser deposition were electrochemically investigated through the interfaces with ionic liquids in a vacuum.</p>

  45. Vapor Deposition Polymerization and Porous Structural Formation of Polyurea Thin Films via Nano-ionic Liquid Films 査読有り

    Rikuto Takahashi, Shingo Maruyama, Yuya Ohsawa, Yuji Matsumoto

    Chemistry Letters 47 (12) 1460-1463 2018年10月

    DOI: 10.1246/cl.180728  

  46. Ionic Conductivity in Ionic Liquid Nano Thin Films 査読有り

    Shingo Maruyama, Ida Bagus Hendra, Prastiawan, Kaho Toyabe, Yuji Higuchi, Tomoyuki Koganezawa, Momoji Kubo, Yuji Matsumoto

    ACS Nano 12 (10) 10509-10517 2018年9月10日

    DOI: 10.1021/acsnano.8b06386  

  47. Molecular Interactions between Pentacene and Imidazolium Ionic Liquids: A Molecular Dynamics Study 査読有り

    Ida Bagus Hendra Prastiawan, Jingxiang Xu, Yusuke Ootani, Yuji Higuchi, Nobuki Ozawa, Shingo Maruyama, Yuji Matsumoto, Momoji Kubo

    Chemistry Letters 47 (9) 1154-1157 2018年9月5日

    出版者・発行元:The Chemical Society of Japan

    DOI: 10.1246/cl.180450  

    ISSN:0366-7022

    eISSN:1348-0715

  48. In situ AFM study of low-temperature polymerization and network formation of thin film polyurea in ionic liquid 査読有り

    Shingo Maruyama, Yuya Ohsawa, Rikuto Takahashi, Yuji Matsumoto

    European Polymer Journal 105 421-425 2018年8月

    出版者・発行元:Elsevier BV

    DOI: 10.1016/j.eurpolymj.2018.06.022  

    ISSN:0014-3057

  49. Electrodeposition of metallic Cu from CuCl gas source transported into ionic liquid in a vacuum 査読有り

    Yosuke Sato, Shingo Maruyama, Yuji Matsumoto

    Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films 36 (3) 31516 2018年5月1日

    出版者・発行元:AVS Science and Technology Society

    DOI: 10.1116/1.5019959  

    ISSN:1520-8559 0734-2101

    詳細を見る 詳細を閉じる

    The authors propose a new electrochemical process combined with vapor-phase deposition. In this process, an ionic liquid (IL) layer of ∼20-μm thickness is used as the electrolyte and then coated on a patterned electrode substrate. The desired source material to electro-deposit is then introduced into the IL layer by vapor deposition in a vacuum under the control of applied electrode potential. In this work, the authors have demonstrated that metallic Cu was electrodeposited in IL by depositing CuCl from the gas phase. At negative electrode potentials versus Cu, CuCl was able to be reduced to metallic Cu, while CuCl remained as-deposited at positive electrode potentials versus Cu. The current density during the electrodeposition was found to strongly correlate with the vapor deposition rate of CuCl at an electrode potential of -0.7 V versus Cu. This suggests that the rate-limiting step in this overpotential region was the vapor deposition rate of CuCl. The rate could then be used to directly modulate the size and density of metallic Cu crystal grains.

  50. In Situ Wettability Characterization of Chemically Heterogeneous Surfaces Probed by Ionic Liquid Contact Angle in Vacuum: Pentacene on Single-Crystal SrTiO3(001) 査読有り

    Takuya Kinoshita, Shingo Maruyama, Yuji Matsumoto

    The Journal of Physical Chemistry C 122 (15) 8390-8395 2018年4月19日

    出版者・発行元:American Chemical Society (ACS)

    DOI: 10.1021/acs.jpcc.8b01128  

    ISSN:1932-7447

    eISSN:1932-7455

  51. Laser Deposition of Nano-ionic Liquids and Their Process Applications in a Vacuum 査読有り

    Yuji Matsumoto, Shingo Maruyama

    RSC Smart Materials 2018- (28) 136-167 2018年

    出版者・発行元:Royal Society of Chemistry

    DOI: 10.1039/9781788011839-00136  

    ISSN:2046-0074 2046-0066

    詳細を見る 詳細を閉じる

    The year 2005, until when ionic liquids (ILs) had been investigated in a vacuum with a common preconception among the research community that they would not evaporate even in vacuum, saw a breakthrough in IL-related research in a vacuum. Since then, there have been many reports on vapor deposition of ILs and related studies. In this chapter, a new deposition method using a continuous wave infrared laser (CW-IR) is proposed to fabricate micro- and nano-ILs this is a promising technique, potentially opening new research fields of nanoscale physics and chemistry of ILs. As one of the applications of such micro- and nano-ILs, a new vacuum process with ILs - IL-assisted vapor synthesis and growth in a vacuum - is also introduced, in which they are used as micro- and nano-scale reactors its applications are now being extended as one of the new chemical routes to various organic, inorganic single crystals and films as well as porous polymer films.

  52. Quantitative Analysis of Nanoscale Step Dynamics in High-Temperature Solution-Grown Single Crystal 4H-SiC via In Situ Confocal Laser Scanning Microscope 査読有り

    Aomi Onuma, Shingo Maruyama, Naoyoshi Komatsu, Takeshi Mitani, Tomohisa Kato, Hajime Okumura, Yuji Matsumoto

    CRYSTAL GROWTH & DESIGN 17 (5) 2844-2851 2017年5月

    出版者・発行元:AMER CHEMICAL SOC

    DOI: 10.1021/acs.cgd.7b00325  

    ISSN:1528-7483

    eISSN:1528-7505

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    Nanoscale understanding of high-temperature crystal growth dynamics in solution has been a challenge to be tackled by many researchers engaged in investigating solution processes for bulk single crystal growth. Here we propose a new approach to in situ observation at a buried solid/liquid interface in high-temperature solution using a conventional confocal laser scanning microscope. In the solution growth of 4H-SiC with Si-Ni based alloy flux as a model system, we show the ability to quantitatively analyze step motions at the growing SiC crystal on the nanoscale at high temperatures up to 1700 degrees C in a vacuum. The temperature-dependent step-advance rates for various steps with different step heights demonstrated the advantageous effect of adding Al to the flux on the step-flow growth of SiC: addition of just 4 at% Al effectively suppressed step-bunching. These experiments point to the importance of in situ nanoscale observation in understanding solution growth mechanisms, and hence the potential to accelerate the development of solution growth processes for high-quality bulk single crystals.

  53. Effects of Al addition to Si-based flux on the growth of 4H-SiC films by vapour–liquid–solid pulsed laser deposition 査読有り

    R. Yamaguchi, A. Osumi, A. Onuma, K. Nakano, S. Maruyama, T. Mitani, T. Kato, H. Okumura, Y. Matsumoto

    19 (35) 5188-5193 2017年

    出版者・発行元:None

    DOI: 10.1039/c7ce00945c  

    ISSN:1466-8033

    eISSN:1466-8033

  54. Ionic liquid-assisted growth of DBTTF–TCNQ complex organic crystals by vacuum co-deposition 査読有り

    Kohei Kuroishi, Shingo Maruyama, Noboru Ohashi, Mio Watanabe, Kenta Naito, Yuji Matsumoto

    453 34-39 2016年11月1日

    出版者・発行元:None

    DOI: 10.1016/j.jcrysgro.2016.07.025  

    ISSN:0022-0248

    eISSN:1873-5002

  55. Direct Synthesis of Porous Polyurea Films by Vapor Deposition Polymerization in Ionic Liquid 査読有り

    Yuya Ohsawa, Rikuto Takahashi, Shingo Maruyama, Yuji Matsumoto

    ACS MACRO LETTERS 5 (9) 1009-1013 2016年9月

    出版者・発行元:AMER CHEMICAL SOC

    DOI: 10.1021/acsmacrolett.6b00594  

    ISSN:2161-1653

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    Most network-structured, porous polymer materials have so far been synthesized in bulk solution processes, which can sometimes be a drawback in their thin-film applications. In this communication, we propose a new route to the direct synthesis of porous polyurea (PU) films by vapor deposition polymerization in ionic liquid (IL), which is based on our original process "IL-assisted vacuum deposition". When 4,4'-methylenebis (2-chlorophenyl isocyanate) (MBCI) and 2,7-diaminofluorene (DAF) monomer molecules were codeposited onto an IL-coated substrate in vacuum, the PU films were found to have a percolated pore and network structure with a high degree of polymerization even without the postannealing treatment, which is required to proceed with the polymerization of PU films in the conventional vapor deposition polymerization. The porous PU film after annealing was still as rigid as the plain PU films and possessed a stronger water repellency, with contact angles exceeding 100 degrees, than the plain PU films.

  56. p-Si(111):H/ionic liquid interface investigated through a combination of electrochemical measurements and reflection high energy electron diffraction surface analysis in vacuum 査読有り

    Ko Watanabe, Shingo Maruyama, Yuji Matsumoto

    CHEMICAL PHYSICS LETTERS 655 6-10 2016年7月

    出版者・発行元:ELSEVIER SCIENCE BV

    DOI: 10.1016/j.cplett.2016.05.026  

    ISSN:0009-2614

    eISSN:1873-4448

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    A combination study of electrochemical measurements and reflection high energy electron diffraction (RHEED) surface analysis experiments in a vacuum was first demonstrated to characterize a p-Si(111): H/ionic liquid interface. Mott-Schottky plot analysis was made to successfully not only evaluate the acceptor density and flat band potential of the p-Si(111):H, but also get some insight into its surface states. Furthermore, the electric double layer capacitance and specific adsorption properties at the IL/Si (111):H interface as well as the electrochemical interface stability will be discussed in this paper. (C) 2016 Elsevier B.V. All rights reserved.

  57. Combinatorial Synthesis of Epitaxial LiCoO₂ Thin Films on SrTiO₃(001) via On-Substrate Sintering of Li₂CO₃ and CoO by Pulsed Laser Deposition 査読有り

    S. Maruyama, O. Kubokawa, K. Nanbu, K. Fujimoto, Y. Matsumoto

    ACS Comb. Sci. 18 (6) 343-348 2016年6月

    出版者・発行元:None

    DOI: 10.1021/acscombsci.6b00027  

    ISSN:2156-8952

    eISSN:2156-8944

  58. アナターゼTiO2エピタキシャル薄膜のPLD合成とin situ測定によるフラットバンド電位の膜厚依存性

    松本 祐司

    表面科学学術講演会要旨集 36 78-78 2016年

    出版者・発行元:公益社団法人 日本表面科学会

    DOI: 10.14886/sssj2008.36.0_78  

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    当研究室オリジナルのPLD-電気化学システムを用いて,NbドープSrTiO3(001)基板上に膜厚の異なるアナターゼTiO2(001)薄膜を作製し,その電気化学特性について,大気暴露せず,Ar雰囲気下,1MのHClO4電解質中で評価を行なった。その結果,成長膜厚の増大とともに,(001)面特有の(1x4)の表面再構成が発達し,フラットバンド電位が,およそ+0.5Vシフトすることを見いだした。

  59. 真空下で蒸着したナノイオン液体の熱脱離挙動

    渡邊 美音, 丸山 伸伍, 松本 祐司

    表面科学学術講演会要旨集 36 342-342 2016年

    出版者・発行元:公益社団法人 日本表面科学会

    DOI: 10.14886/sssj2008.36.0_342  

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    我々は近年,独自の真空蒸着法により,ナノレベルでのイオン液体の液滴及び液膜の作製に取り組んでいる.これらは,バルクのイオン液体とは異なる構造やイオン伝導性などの特異な物性を示す一方で,真空蒸着過程における薄膜・結晶成長の溶媒としてなど,様々な真空材料プロセスへの応用が期待されている.本研究では昇温脱離質量分析計を用いることで,ナノイオン液体の熱安定性と脱離過程についての評価を試みた.

  60. 融点が室温以上のイオン液体の真空蒸着と構造評価

    吉井 彩, 松本 祐司, 丸山 伸伍

    表面科学学術講演会要旨集 36 343-343 2016年

    出版者・発行元:公益社団法人 日本表面科学会

    DOI: 10.14886/sssj2008.36.0_343  

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    融点が室温以上のイオン液体を真空下で赤外レーザーを用いて固体基板上に蒸着し,蒸着膜の構造を評価した.NMR構造解析結果から,今回用いたイオン液体は真空蒸着しても分解しないことが明らかになった.また,蒸着膜のAFM観察において,粒子状の島が多く観察され,これらは固体状態で蒸着していると推測された.そして,粉末XRD解析結果からは,結晶化していることが示唆された.

  61. Uniform growth of SiC single crystal thin films via a metal-Si alloy flux by vapour-liquid-solid pulsed laser deposition: the possible existence of a precursor liquid flux film 査読有り

    Aomi Onuma, Shingo Maruyama, Takeshi Mitani, Tomohisa Kato, Hajime Okumura, Yuji Matsumoto

    CRYSTENGCOMM 18 (1) 143-148 2016年

    出版者・発行元:ROYAL SOC CHEMISTRY

    DOI: 10.1039/c5ce01865j  

    ISSN:1466-8033

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    For their use as next generation power semiconductors, new vapor growth processes for SiC single crystal films have been highly demanded, among which is the vapor-liquid-solid (VLS) growth with a metal-Si flux. If the metal-Si flux liquid were highly wettable on SiC, a thinner flux liquid layer would be favored for a higher growth rate in the VLS process. We demonstrated that a thin NiSi2 layer, even as small as 150 nm in thickness to form liquid droplets, could work effectively as a flux in the pulsed laser deposition (PLD)-based VLS process for the uniform growth of high-quality 3C-SiC (111) films on 4H-SiC (0001). In situ direct observation of the interface between the flux and single crystal SiC using a laser microscope strongly implied the existence of a precursor liquid flux film spreading between the NiSi2 droplets that can have a similar role in the flux growth process, resulting in significant improvements in the surface morphology, crystallinity as well as stoichiometry of SiC films.

  62. Thickness-Dependent Flat Band Potential of Anatase TiO2(001) Epitaxial Films on Nb:SrTiO3(001) Investigated by UHV-Electrochemistry Approach 査読有り

    Yuji Matsumoto, Yoshihiro Miura, Shintaro Takata

    JOURNAL OF PHYSICAL CHEMISTRY C 120 (3) 1472-1477 2016年1月

    出版者・発行元:AMER CHEMICAL SOC

    DOI: 10.1021/acs.jpcc.5b08708  

    ISSN:1932-7447

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    The semiconductor characteristics of anatase TiO2(001) films, which were pulsed laser-deposited on a 0.05 wt % Nb-doped SrTiO3(001) single crystal electrode, as well as the film/electrolyte heterointerfaces were investigated by the ultrahigh-vacuum electrochemistry approach. In addition to the current voltage measurements, equivalent circuit modeling in electrochemical impedance spectroscopy at different electrode potentials reveals that the flat band potential of anatase TiO2 films shifts by +0.5 V when the film thickness increases with (1 x 4) surface reconstruction more visible in reflection high energy electron diffraction. The possible origins of the observed flat band potential shift will be discussed from the viewpoint of electric double layer effects, mainly of donor-type surface states and surface reconstruction, compared with the results of single crystal rutile TiO2(110).

  63. Effect of Al addition to Si–Ni flux on pulsed laser deposition of SiC thin films 査読有り

    Aomi ONUMA, Shingo MARUYAMA, Takeshi MITANI, Tomohisa KATO, Hajime OKUMURA, Yuji MATSUMOTO

    124 (5) 506-509 2016年

    出版者・発行元:None

    DOI: 10.2109/jcersj2.15256  

    ISSN:1882-0743

    eISSN:1348-6535

  64. Epitaxial growth of atomically flat KBr(111) films via a thin film ionic liquid in a vacuum 査読有り

    M. Yamauchi, S. Maruyama, N. Ohashi, K. Toyabe, Y. Matsumoto

    CrystEngComm 18 (19) 3399-3403 2016年

    出版者・発行元:Royal Society of Chemistry (RSC)

    DOI: 10.1039/c6ce00620e  

    ISSN:1466-8033

    eISSN:1466-8033

  65. Large negative magnetic anisotropy of W/Fe/W (001) epitaxial trilayers 査読有り

    Y. Matsumoto, S. Okamoto, N. Kikuchi, O. Kitakami, Y. Miura, M. Suzuki, M. Mizumaki, N. Kawamura

    IEEE Transactions on Magnetics 51 2100704 2015年11月

    DOI: 10.1109/TMAG.2015.2432074  

  66. Intrinsic Nature of Interfacial Interactions between Ionic Liquids and Rutile TiO₂ Single Crystal Surfaces Studied by in Situ Contact Angle Measurement in a Vacuum 査読有り

    Shingo Maruyama, Yuji Matsumoto

    119 (31) 17755-17761 2015年8月6日

    出版者・発行元:None

    DOI: 10.1021/acs.jpcc.5b05276  

    ISSN:1932-7447

    eISSN:1932-7455

  67. Effect of aluminum addition on the surface step morphology of 4H-SiC grown from Si-Cr-C solution 査読有り

    Takeshi Mitani, Naoyoshi Komatsu, Tetsuo Takahashi, Tomohisa Kato, Shunta Harada, Toru Ujihara, Yuji Matsumoto, Kazuhisa Kurashige, Hajime Okumura

    JOURNAL OF CRYSTAL GROWTH 423 45-49 2015年8月

    出版者・発行元:ELSEVIER SCIENCE BV

    DOI: 10.1016/j.jcrysgro.2015.04.032  

    ISSN:0022-0248

    eISSN:1873-5002

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    For the solution growth of 4H-SiC with Si1-xCrx solvents, the change in surface step structure by 4 at% Al addition to the solvent was investigated. Without Al addition, step bunching resulted in the formation of giant macrosteps with height greater than several micrometers, and trench-like surface defects formed with solvent inclusion. The edge of the giant macrosteps composing trench-like defects was faceted into low-index facet planes, (1 (1) over bar 0m) (m=1-4). The formation of the trench-like surface defects is considered to originate from the self-pinning of macrosteps owing to the step-faceting phenomenon, which facilitates further development of macrosteps. On the other hand, the addition of Al to the solvents significantly improved the surface roughening, and suppressed the formation of the trench-like surface defects. In this case, smaller bunched steps with heights from several nanometers to about 10 nm formed on the terraces of the macrosteps, while regularly arranged trains of unit-cell-size steps formed on the terrace of macrosteps in growth without Al addition. The decrease in step stiffness might be a possible cause for the formation of the smaller bunched steps on the terrace in growth with Al addition. (C) 2015 Elsevier B.V. All rights reserved.

  68. 4H-SiC growth from Si-Cr-C solution under Al and N Co-doping conditions 査読有り

    Takeshi Mitani, Naoyoshi Komatsu, Tetsuo Takahashi, Tomohisa Kato, Toru Ujihara, Yuji Matsumoto, Kazuhisa Kurashige, Hajime Okumura

    Materials Science Forum 821-823 9-13 2015年

    出版者・発行元:Trans Tech Publications Ltd

    DOI: 10.4028/www.scientific.net/MSF.821-823.9  

    ISSN:0255-5476

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    We have investigated solution growth of 4H-SiC under various Al-N co-doping conditions. Both p-type and n-type 4H-SiC were successfully grown under Al-N co-doping conditions where we added Al to stabilize both growth surface morphology and polytype. The doping and electrical properties were investigated systematically. Interaction between Al and N in the incorporation process and electrical property under heavily co-doped conditions were discussed.

  69. Change in surface morphology by addition of impurity elements in 4H-SiC solution growth with Si solvent 査読有り

    Naoyoshi Komatsu, Takeshi Mitani, Tetsuo Takahashi, Tomohisa Kato, Kazuhisa Kurashige, Yuji Matsumoto, Toru Ujihara, Hajime Okumura

    Materials Science Forum 821-823 14-17 2015年

    出版者・発行元:Trans Tech Publications Ltd

    DOI: 10.4028/www.scientific.net/MSF.821-823.14  

    ISSN:0255-5476

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    In solution growth of 4H-SiC, we have investigated changes in macrostep height with addition of the Group III (B, Al, Ga), Group IV (Ge, Sn), Group V (N) elements, and transition metals (Ti, V, Cr, Ni) to Si solvents, in order to find additives improving severe step bunching which often occurs during growth. The addition of Al, B, Sn, N, and V decreased the average macrostep height compared with the crystal grown with Si solvents. The addition of Al, B, Sn, N, and V suppressed the generation of trench-shaped surface defects in long-term growth of 10 hours. This result demonstrated that the addition of Al, B, Sn, N, and V has an advantage to achieve high quality bulk crystal growth from solution.

  70. Effect of forced convection by crucible design in solution growth of SiC single crystal 査読有り

    Kazuhisa Kurashige, Masahiro Aoshima, Koichi Takei, Kuniharu Fujii, Masahiko Hiratani, Nachimuthu Senguttuvan, Tomohisa Kato, Toru Ujihara, Yuji Matsumoto, Hajime Okumura

    Materials Science Forum 821-823 22-25 2015年

    出版者・発行元:Trans Tech Publications Ltd

    DOI: 10.4028/www.scientific.net/MSF.821-823.22  

    ISSN:0255-5476

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    In this paper, we will discuss how to cope with the smoother growth front and higher growth rate by the forced convection. When the rotation rate of the upper part of the solution is different from that of the lower part in the crucible, the centrifugal force of the upper part is different from that of the lower part. As a result, a forced convection occurs in the solution. This kind of convection was achieved with accelerating/decelerating rotation of crucible and a plate fixed on the bottom of the crucible. By optimizing conditions of rotation program patterns and the crucible design for the forced convection, the growth rate could almost be doubled while maintaining smooth morphology.

  71. Influences of solution flow and lateral temperature distribution on surface morphology in solution growth of SiC 査読有り

    Kuniharu Fujii, Koichi Takei, Masahiro Aoshima, Nachimuthu Senguttuvan, Masahiko Hiratani, Toru Ujihara, Yuji Matsumoto, Tomohisa Kato, Kazuhisa Kurashige, Hajime Okumura

    Materials Science Forum 821-823 35-38 2015年

    出版者・発行元:Trans Tech Publications Ltd

    DOI: 10.4028/www.scientific.net/MSF.821-823.35  

    ISSN:0255-5476

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    The influences of solution flow and lateral temperature distribution on the surface morphology of 4H-SiC single crystal grown from solution was investigated. A flat surface region was enlarged by the seed-rotation rate. The solution flow simulation indicated that the higher rotation rate made the outward solution flow ordered beneath the solution surface. Such a solution flow was thought to be effective to enlarge the flat region of the growth front. Furthermore, a full-flat surface was obtained with a hollow-type graphite rod at a seed-rotation rate of 60 min-1. The simulated results of temperature distribution showed that the hollow-type graphite rod reduced the lateral temperature gradient at the SiC-solution interface. The ordered solution flow and the small temperature gradient at the growth front were found to be effective to make the growth front flat in the solution-growth method.

  72. Photoelectrochemical epitaxy of silver oxide clathrate Ag7O8M (M = NO3, HSO4) on rutile-type Nb-doped TiO2single crystals 査読有り

    Ryohei Tanaka, Ryota Takahashi, Shintaro Takata, Mikk Lippmaa, Yuji Matsumoto

    CrystEngComm 17 (19) 3701-3707 2015年

    出版者・発行元:Royal Society of Chemistry (RSC)

    DOI: 10.1039/c5ce00329f  

    ISSN:1466-8033

    eISSN:1466-8033

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    <p>Silver oxide clathrate Ag<sub>7</sub>O<sub>8</sub>NO<sub>3</sub>epitaxial films were synthesized photo-electrochemically on rutile-type Nb-doped TiO<sub>2</sub>(110) single-crystal substrates.</p>

  73. Growth rate and surface morphology of 4H-SiC crystals grown from Si-Cr-C and Si-Cr-Al-C solutions under various temperature gradient conditions 査読有り

    Takeshi Mitani, Naoyoshi Komatsu, Tetsuo Takahashi, Tomohisa Kato, Kuniharu Fujii, Toru Ujihara, Yuji Matsumoto, Kazuhisa Kurashige, Hajime Okumura

    401 681-685 2014年9月

    出版者・発行元:None

    DOI: 10.1016/j.jcrysgro.2013.11.031  

    ISSN:0022-0248

    eISSN:1873-5002

  74. Deterministic arbitrary switching of polarization in a ferroelectric thin film 査読有り

    R. K. Vasudevan, Y. Matsumoto, Xuan Cheng, A. Imai, S. Maruyama, H. L. Xin, M. B. Okatan, S. Jesse, S. V. Kalinin, V. Nagarajan

    NATURE COMMUNICATIONS 5 4971 2014年9月

    出版者・発行元:NATURE PUBLISHING GROUP

    DOI: 10.1038/ncomms5971  

    ISSN:2041-1723

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    Ferroelectrics have been used as memory storage devices, with an upper bound on the total possible memory levels generally dictated by the number of degenerate states allowed by the symmetry of the ferroelectric phase. Here, we introduce a new concept for storage wherein the polarization can be rotated arbitrarily, effectively decoupling it from the crystallographic symmetry of the ferroelectric phase on the mesoscale. By using a Bi5Ti3FeO15-CoFe2O4 film and via Band-Excitation Piezoresponse Force Microscopy, we show the ability to arbitrarily rotate polarization, create a spectrum of switched states, and suggest the reason for polarization rotation is an abundance of sub-50 nm nanodomains. Transmission electron microscopy-based strain mapping confirms significant local strain undulations imparted on the matrix by the CoFe2O4 inclusions, which causes significant local disorder. These experiments point to controlled tuning of polarization rotation in a standard ferroelectric, and hence the potential to greatly extend the attainable densities for ferroelectric memories.

  75. Nondestructive and repeatable capacitance–voltage and current–voltage measurements across the oxide/electrolyte interface by UHV-electrochemistry approach 査読有り

    Yoshihiro Miura, Shintaro Takata, Yuji Matsumoto

    Applied Physics Express 7 (9) 095802-095802 2014年9月1日

    出版者・発行元:None

    DOI: 10.7567/APEX.7.095802  

    ISSN:1882-0786 1882-0778

    eISSN:1882-0786

  76. Growth behaviours of pentacene films confined in engineered shapes of ionic-liquid in vacuum 査読有り

    Yoko Takeyama, Shinji Mantoku, Shingo Maruyama, Yuji Matsumoto

    CRYSTENGCOMM 16 (4) 684-689 2014年

    出版者・発行元:ROYAL SOC CHEMISTRY

    DOI: 10.1039/c3ce41473f  

    ISSN:1466-8033

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    Ionic liquid (IL) films not only in the form of micro-droplets, but also of a homogeneously thick submicron-layer were deposited under vacuum on indium tin oxide (ITO) substrates by chemically modifying their wettability to the substrate. When pentacene was deposited on these IL-coated ITO substrates, pentacene crystals were grown via the IL. Depending on the shape and size of the IL films: a small-droplet (phi: 5 mu m), a large-droplet (phi: 20 mu m) and a homogeneously thick layer (about 0.1 mu m in thickness), there were found significant differences in the growth behaviour of pentacene and the resultant adhesion ability of these pentacene films to the substrate, the mechanism of which is discussed with the aid of in situ observation of the crystal growth process in the IL in view of the wettability of the IL, the nucleation and the subsequent growth of the pentacene crystals.

  77. Evidence for the intrinsic nature of band-gap states electrochemically observed on atomically flat TiO2(110) surfaces 査読有り

    Shintaro Takata, Yoshihiro Miura, Yuji Matsumoto

    PHYSICAL CHEMISTRY CHEMICAL PHYSICS 16 (45) 24784-24799 2014年

    出版者・発行元:ROYAL SOC CHEMISTRY

    DOI: 10.1039/c4cp03280b  

    ISSN:1463-9076

    eISSN:1463-9084

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    Using an ultra-high vacuum (UHV) electrochemistry approach with pulsed laser deposition (PLD), we investigated the band-gap state for TiO2(110). In the PLD chamber, a TiO2(110) surface was cleaned by annealing in O-2 enough for it to exhibit a sharp (1 x 1) reflection high energy electron diffraction (RHEED) pattern. The cleaned TiO2(110)-(1 x 1) sample then underwent electrochemical measurements without exposure to air, showing the band-gap state at -0.14 V vs. Ag by Mott-Schottky plot analysis. The band-gap state gradually disappeared under UV illumination at +0.6 V vs. Ag due to photoetching, and reappeared on reduction in a vacuum and/or deposition of a fresh TiO2 film. These results indicated that the electrochemically observed band-gap state for TiO2(110) was a defect state due to oxygen deficiency, most probably identical to that observed under UHV, which does not necessarily exist on the surface. A quantitative analysis of the defect density suggests that the origin of this defect state is not the surface bridging hydroxyls or oxygen vacancies, but rather the interstitial Ti3+ ions in the subsurface region.

  78. Epitaxial Bi5Ti3FeO15-CoFe 2O4 Pillar-matrix multiferroic nanostructures 査読有り

    Akira Imai, Xuan Cheng, Huolin L. Xin, Eugene A. Eliseev, Anna N. Morozovska, Sergei V. Kalinin, Ryota Takahashi, Mikk Lippmaa, Yuji Matsumoto, Valanoor Nagarajan

    ACS Nano 7 (12) 11079-11086 2013年12月23日

    DOI: 10.1021/nn404779x  

    ISSN:1936-0851 1936-086X

    詳細を見る 詳細を閉じる

    Epitaxial self-assembled ferro(i)magnetic spinel (CoFe2O 4 (CFO)) and ferroelectric bismuth layered perovskite (Bi 5Ti3FeO15 (BTFO)) pillar-matrix nanostructures are demonstrated on (001) single-crystalline strontium titanate substrates. The CFO remains embedded in the BTFO matrix as vertical pillars (∼50 nm in diameter) up to a volume fraction of 50%. Piezoresponse force microscopy experiments evidence a weak out-of-plane and a strong in-plane ferroelectricity in the BTFO phase, despite previously reported paraelectricity along the c-axis in a pure BTFO film. Phenomenological Landau-Ginzburg-Devonshire-based thermodynamic computations show that the radial stress induced by the CFO nanopillars can influence these ferroelectric phases, thus signifying the importance of the nanopillars. The CFO pillars demonstrate robust ferromagnetic hysteresis loops with little degradation in the saturation magnetization (ca. 4 μB/f.u.). Thus BTFO-CFO nanocomposites show significant promise as a lead-free magnetoelectric materials system. © 2013 American Chemical Society.

  79. High-Throughput Screening of Si-Ni Flux for SiC Solution Growth Using a High-Temperature Laser Microscope Observation and Secondary Ion Mass Spectroscopy Depth Profiling 査読有り

    Shingo Maruyama, Aomi Onuma, Kazuhisa Kurashige, Tomohisa Kato, Hajime Okumura, Yuji Matsumoto

    ACS COMBINATORIAL SCIENCE 15 (6) 287-290 2013年6月

    出版者・発行元:AMER CHEMICAL SOC

    DOI: 10.1021/co400009z  

    ISSN:2156-8952

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    Screening of Si-based flux materials for solution growth of SiC single crystals was demonstrated using a thin film composition-spread technique. The reactivity and diffusion of carbon in a composition spread of the flux was investigated by secondary ion mass spectroscopy depth profiling of the annealed flux thin film spread on a graphite substrate. The composition dependence of the chemical interaction between a seed crystal and flux materials was revealed by high-temperature thermal behavior observation of the flux and the subsequent morphological study of the surface after removing the flux using atomic force microscopy. Our new screening approach is shown to be an efficient process for understanding flux materials for SiC solution growth.

  80. In-situ observations of flux growth of NaTaO₃ crystals on tantalum substrate 査読有り

    Sayaka Suzuki, Katsuya Teshima, Shingo Maruyama, Yuji Matsumoto, Kazunari Domen, Shuji Oishi

    CrystEngComm 15 (20) 4058-4061 2013年5月28日

    出版者・発行元:None

    DOI: 10.1039/c3ce40330k  

    ISSN:1466-8033

    eISSN:1466-8033

  81. Combinatorial Nanoscience and Technology for Solid-State Materials 査読有り

    Hideomi Koinuma, Ryota Takahashi, Mikk Lippmaa, Se-Young Jeong, Yuji Matsumoto, Toyohiro Chikyo, Setsu Suzuki

    Handbook of Advanced Ceramics: Materials, Applications, Processing, and Properties: Second Edition 1103-1124 2013年5月1日

    出版者・発行元:Elsevier Inc.

    DOI: 10.1016/B978-0-12-385469-8.00057-5  

  82. Large Tunnel Magnetoresistance in Epitaxial Oxide Spin-Filter Tunnel Junctions 査読有り

    Takayuki Harada, Isao Ohkubo, Mikk Lippmaa, Yasuaki Sakurai, Yuji Matsumoto, Shunsuke Muto, Hideomi Koinuma, Masaharu Oshima

    ADVANCED FUNCTIONAL MATERIALS 22 (21) 4471-4475 2012年11月

    出版者・発行元:WILEY-V C H VERLAG GMBH

    DOI: 10.1002/adfm.201200985  

    ISSN:1616-301X

    eISSN:1616-3028

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    A high-performance spin filter tunnel junction composed of an epitaxial oxide heterostructure is reported. By independently controlling the magnetic orientations of ferromagnetic tunnel barrier and electrode layers, a tunnel magnetoresistance ratio exceeding 120% is obtained purely by the spin filtering effect. A newly introduced spin filter material, Pr0.8Ca0.2Mn1-yCoyO3, is shown to be useful for building novel multibarrier spintronic tunnel devices due to its composition-controlled magnetic hardness.

  83. Development of a new laser heating system for thin film growth by chemical vapor deposition 査読有り

    Eiji Fujimoto, Masatomo Sumiya, Tsuyoshi Ohnishi, Mikk Lippmaa, Masaki Takeguchi, Hideomi Koinuma, Yuji Matsumoto

    REVIEW OF SCIENTIFIC INSTRUMENTS 83 (9) 094701 2012年9月

    出版者・発行元:AMER INST PHYSICS

    DOI: 10.1063/1.4748126  

    ISSN:0034-6748

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    We have developed a new laser heating system for thin film growth by chemical vapor deposition (CVD). A collimated beam from a high-power continuous-wave 808 nm semiconductor laser was directly introduced into a CVD growth chamber without an optical fiber. The light path of the heating laser inside the chamber was isolated mechanically from the growth area by bellows to protect the optics from film coating. Three types of heat absorbers, (10 x 10 x 2 mm(3)) consisting of SiC, Ni/NiOx, or pyrolytic graphite covered with pyrolytic BN (PG/PBN), located at the backside of the substrate, were tested for heating performance. It was confirmed that the substrate temperature could reach higher than 1500 degrees C in vacuum when a PG/PBN absorber was used. A wide-range temperature response between 400 degrees C and 1000 degrees C was achieved at high heating and cooling rates. Although the thermal energy loss increased in a H-2 gas ambient due to the higher thermal conductivity, temperatures up to 1000 degrees C were achieved even in 200 Torr H-2. We have demonstrated the capabilities of this laser heating system by growing ZnO films by metalorganic chemical vapor deposition. The growth mode of ZnO films was changed from columnar to lateral growth by repeated temperature modulation in this laser heating system, and consequently atomically smooth epitaxial ZnO films were successfully grown on an a-plane sapphire substrate. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4748126]

  84. Spin-Filter Tunnel Junction with Matched Fermi Surfaces 査読有り

    T. Harada, I. Ohkubo, M. Lippmaa, Y. Sakurai, Y. Matsumoto, S. Muto, H. Koinuma, M. Oshima

    PHYSICAL REVIEW LETTERS 109 (7) 076602 2012年8月

    出版者・発行元:AMER PHYSICAL SOC

    DOI: 10.1103/PhysRevLett.109.076602  

    ISSN:0031-9007

    eISSN:1079-7114

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    Efficient injection of spin-polarized current into a semiconductor is a basic prerequisite for building semiconductor-based spintronic devices. Here, we use inelastic electron tunneling spectroscopy to show that the efficiency of spin-filter-type spin injectors is limited by spin scattering of the tunneling electrons. By matching the Fermi-surface shapes of the current injection source and target electrode material, spin injection efficiency can be significantly increased in epitaxial ferromagnetic insulator tunnel junctions. Our results demonstrate that not only structural but also Fermi-surface matching is important to suppress scattering processes in spintronic devices.

  85. Effects of V-Ion Doping on the Photoelectrochemical Properties of Epitaxial TiO2(110) Thin Films on Nb-Doped TiO2 (110) Single Crystals 査読有り

    Atsushi Hachiya, Shintaro Takata, Yutaro Komuro, Yuji Matsumoto

    JOURNAL OF PHYSICAL CHEMISTRY C 116 (32) 16951-16956 2012年8月

    出版者・発行元:AMER CHEMICAL SOC

    DOI: 10.1021/jp307185d  

    ISSN:1932-7447

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    V-doped TiO2(110) epitaxial films were grown on atomically flat Nb-doped TiO2 (110) single-crystal substrates by a pulsed laser deposition method, and their photoelectrochemical properties were investigated. In the photocurrent-potential curves measured in a 0.1 M HClO4 electrolyte for V-doped TiO2/Nb-doped TiO2 photoelectrodes, the photocurrent was almost proportional to the electrode potential, and there was a good linear relationship between the inverse of the photocurrent density obtained at +0.6 V versus Ag/AgCl KCl (sat.) and the V doping level. The potential at which the photocurrent appeared, that is, the flat-band potential, was about +0.33 V irrespective of the doping level, whereas it was about -0.25 V for the nondoped one. When a 0.01 M AgNO3 electrolyte was used, a sizable amount of Ag metal particles was deposited at +0.25 V on the electrode surfaces at V doping levels above 6 at %. The V-doping effects on these photoelectrochemical properties are discussed in terms of the in-gap states induced by the V impurities in TiO2 as well as their acting not only as a recombination center but also as a mediator of interfacial electron transfer.

  86. Organic single crystal transistor characteristics of single-crystal phase pentacene grown by ionic liquid-assisted vacuum deposition 査読有り

    Yoko Takeyama, Shimpei Ono, Yuji Matsumoto

    APPLIED PHYSICS LETTERS 101 (8) 083303 2012年8月

    出版者・発行元:AMER INST PHYSICS

    DOI: 10.1063/1.4747148  

    ISSN:0003-6951

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    Organic transistor characteristics of single-crystal phase pentacene were investigated. Ionic liquids (ILs) were used as not only a gate dielectric material in the transistors but also a crystallization solvent in vacuum deposition of pentacene. The crystal sizes reached 200 mu m and their surface exhibits a molecularly step-and-terrace structure. There was no sign of IL molecules inside the crystal, and the impurity level of 6,13-pentacenequinone was also reduced. The average value of the field-effect mobility was not so inferior to those for the conventional pentacene single crystals, and the highest value exceeded 5 cm(2)/Vs, with the on/off current ratio of 10(4). (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4747148]

  87. 真空蒸着法によるイオン液体中有機単結晶の育成とFET特性評価

    武山洋子, 小野新平, 松本祐司

    電子情報通信学会技術研究報告 112 (57(OME2012 19-31)) 7-11 2012年5月17日

    出版者・発行元:一般社団法人電子情報通信学会

    ISSN:0913-5685

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    有機単結晶デバイスは近年、高い移動度が報告され注目を集めている。我々は高品質な結晶育成法として溶液を介した真空蒸着法を検討してきており、特に有機結晶の育成にはイオン液体が効果的であることを見出してきた。そこで今回、イオン液体中で育成したペンタセン単結晶を用いた有機トランジスタ特性の評価を試みた。ペンタセンを真空中のイオン液体液滴に蒸着することによって溶液内で板状の単結晶が成長し、その結晶サイズは200μmに達した。その結晶表面には明瞭なステップ&テラスが見られるなど、高品質な結晶であった。さらに、この結晶を用いた有機トランジスタ評価にはイオン液体をゲート層として使用し、比較的高い移動度が達成された。

  88. Field-effect transistors of the block co-oligomers based on thiophene and pyridine 査読有り

    Masamitsu Haemori, Kenji Itaka, Jun Yamaguchi, Akira Kumagai, Seiichiro Yaginuma, Hiroki Fukumoto, Yuji Matsumoto, Takakazu Yamamoto, Hideomi Koinuma

    THIN SOLID FILMS 520 (13) 4445-4448 2012年4月

    出版者・発行元:ELSEVIER SCIENCE SA

    DOI: 10.1016/j.tsf.2012.02.026  

    ISSN:0040-6090

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    We have investigated the structural and electrical characteristics of two kinds of block co-oligomers, 5,5"-Bis(2-pyridyl)-2,2':5',2"-terthiophene (5A) and 2,5-Bis(2-(2'-thienyl)-pyridine-5-yl)thiophene (5B), which are composed of electron-donating thiophene and electron-withdrawing pyridine rings. At the view of building block units, the amount of the module units included in these molecules is completely equivalent to each other. X-ray diffraction patterns of 5A and 5B thin films grown on atomically flat alpha-Al2O3 (0001) substrates indicated a high degree of orientation along the c-axis. Field-effect transistors (FETs) of 5A and 5B thin films were fabricated and evaluated without exposure to air. The FETs based on 5A active layers exhibited p-type behavior with a mobility of similar to 10(-3)cm(2)/V.s and an on-off ratio of 10(4), while no switching behavior was observed in FETs based on 5B active layers. The lower highest occupied molecular orbital (HOMO) of 5B than that of 5A in the quantum-chemical calculation might explain these FET behaviors. Thus, HOMO, lowest unoccupied molecular orbital (LUMO) levels and FET actions of the co-oligomer molecules that consist of the same amount of building blocks can be controlled by the sequence of electron-donating and electron-withdrawing building blocks. (C) 2012 Elsevier B.V. All rights reserved.

  89. 光触媒作用はなぜ再現しないことが多いのか?

    松本 祐司

    表面科学学術講演会要旨集 32 111-111 2012年

    出版者・発行元:公益社団法人 日本表面科学会

    DOI: 10.14886/sssj2008.32.0_111  

    詳細を見る 詳細を閉じる

    光触媒作用は再現しないことが多い。光触媒が単なる表面で起こる光誘起の触媒ではなく、バルクでの少数キャリアの光励起とのその拡散、界面での電荷移動を伴う半導体デバイスだからである。そこでは、従来の表面分析手法では検出限界以下の欠陥や不純物が、その半導体物性の制御を困難にしている。本講演では、これら欠陥や不純物の光触媒作用に及ぼす効果について、表面科学的にどのようにアプローチできるか、考えてみたい。

  90. Photo-Electrochemical Synthesis of Silver-Oxide Clathrate Ag7O8NO3 on SrTiO3 査読有り

    R. Tanaka, S. Takata, R. Takahashi, J. K. Grepstad, T. Tybell, Y. Matsumoto

    ELECTROCHEMICAL AND SOLID STATE LETTERS 15 (4) E19-E22 2012年

    出版者・発行元:ELECTROCHEMICAL SOC INC

    DOI: 10.1149/2.015204esl  

    ISSN:1099-0062

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    Photo-electrochemical synthesis of silver-oxide clathrate Ag7O8NO3 on Nb-doped SrTiO3(001) single crystal electrodes in AgNO3 aqueous solutions was studied. The formation of small plate-like grains on the electrode first occurred, followed by the growth of large faceted crystals. The selectivity for the photocatalytic oxidation products Ag7O8NO3 and O-2 was found to depend on the electrode potential. A lower electrode potential resulted in preferential deposition of Ag7O8NO3 over O-2 evolution. This result suggests that the role of the electrode potential in this photochemical process is to control the interface reaction kinetics, as well as the separation of photo-excited electron-hole pairs in bulk. (C) 2012 The Electrochemical Society. [DOI:10.1149/2.015204esl] All rights reserved.

  91. Ionic liquid-mediated epitaxy of high-quality C-60 crystallites in a vacuum 査読有り

    Yoko Takeyama, Shingo Maruyama, Hiroki Taniguchi, Mitsuru Itoh, Keiji Ueno, Yuji Matsumoto

    CRYSTENGCOMM 14 (15) 4939-4945 2012年

    出版者・発行元:ROYAL SOC CHEMISTRY

    DOI: 10.1039/c2ce25163a  

    ISSN:1466-8033

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    Ionic liquid-mediated vacuum deposition was demonstrated as a novel growth technique for high-quality C-60 crystallites. In this process the ionic liquid worked as a solvent, i.e. the gas phase C-60 precursors were continuously fed into the ionic liquid on a substrate in a vacuum chamber, from which the nucleation and the subsequent growth of C-60 crystallites proceeded. The impact of varying the substrate on the growth behaviour was intensively examined in terms of not only the lattice-mismatch between C-60 and the substrates, but also the wetting behavior of the ionic liquid on the substrates. This led to a significant improvement of the C-60 crystallinity and epitaxial growth was successfully found on certain substrates. In particular, molecularly smooth and thick C-60 hexagonal-shaped crystallites epitaxially grew on a MoS2 substrate, the average size of which reached as large as 10 mm.

  92. Non-linear electric field response of permittivity of atomically smooth TiO₂(rutile) single crystals studied by an electrochemical approach 査読有り

    Shintaro TAKATA, Atsushi HACHIYA, Yuji MATSUMOTO

    Journal of the Ceramic Society of Japan 120 (1405) 366-369 2012年

    出版者・発行元:None

    DOI: 10.2109/jcersj2.120.366  

    ISSN:1882-0743

    eISSN:1348-6535

  93. Nanoscale oxygen nonstoichiometry in epitaxial TiO₂ films grown by pulsed laser deposition 査読有り

    Takata, Shintaro Tanaka, Ryohei Hachiya, Atsushi Matsumoto, Yuji

    J. Appl. Phys. 110 (10) 103513 2011年11月

    出版者・発行元:None

    DOI: 10.1063/1.3662199  

    ISSN:0021-8979

  94. High-throughput CW-IR laser deposition and laser microscope imaging of binary ionic liquids in vacuum 査読有り

    Shingo Maruyama, Hiroki Taniguchi, Yoko Takeyama, Mitsuru Itoh, Yuji Matsumoto

    SCIENCE AND TECHNOLOGY OF ADVANCED MATERIALS 12 (5) 054204 2011年10月

    出版者・発行元:TAYLOR & FRANCIS LTD

    DOI: 10.1088/1468-6996/12/5/054204  

    ISSN:1468-6996

    eISSN:1878-5514

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    A combinatorial library of binary mixtures of ionic liquids with various mixing ratios was fabricated on a single sapphire substrate using the composition-spread technique combined with a continuous-wave infrared (CW-IR) laser deposition method; the mixtures were condensed in the form of micro-scale droplets. The mixing ratio within the droplets was examined by Raman spectroscopy. The contact angle of the droplets was found to systematically vary with the mixing ratio. Their thermal behavior was characterized with an ultrahigh-vacuum laser microscope, revealing the dependence of the evaporation rate on the mixing ratio.

  95. Development of compact CW-IR laser deposition system for high-throughput growth of organic single crystals 査読有り

    Yoko Takeyama, Shingo Maruyama, Yuji Matsumoto

    Science and Technology of Advanced Materials 12 (5) 054210 2011年10月

    出版者・発行元:None

    DOI: 10.1088/1468-6996/12/5/054210  

    ISSN:1468-6996

  96. Screening of metal flux for SiC solution growth by a thin-film combinatorial method 査読有り

    Yoshiyuki Yonezawa, Mina Ryo, Aki Takigawa, Yuji Matsumoto

    SCIENCE AND TECHNOLOGY OF ADVANCED MATERIALS 12 (5) 054209 2011年10月

    出版者・発行元:NATL INST MATERIALS SCIENCE

    DOI: 10.1088/1468-6996/12/5/054209  

    ISSN:1468-6996

    詳細を見る 詳細を閉じる

    4H-SiC is a wide-bandgap semiconductor with potential applications in power devices. The lack of a liquid phase in SiC hinders conventional crystal growth from the melt; consequently, SiC wafers still have low quality and are nearly 100 times more expensive than Si wafers. To take advantage of the solution growth for improving the quality and reducing the cost of SiC, Ni addition to Si-Ti flux has been investigated. A combinatorial approach was employed to accelerate the screening of metal flux for the SiC solution growth.

  97. Enhancement of Quantum Ferroelectricity in SrTi18O₃ Thin Film 査読有り

    Yasuhiro Fujii, Yuki Maeda, Masao Katayama, Hiroki Taniguchi, Hiroshi Takashima, Mitsuru Itoh, Yuji Matsumoto

    Applied Physics Express 4 (9) 091501-091501 2011年9月

    出版者・発行元:None

    DOI: 10.1143/APEX.4.091501  

    ISSN:1882-0778

    eISSN:1882-0786

  98. Influence of substrates on epitaxial growth of B-site-ordered perovskite La2NiMnO6 thin films 査読有り

    Y. Sakurai, I. Ohkubo, Y. Matsumoto, H. Koinuma, M. Oshima

    JOURNAL OF APPLIED PHYSICS 110 (6) 063913 2011年9月

    出版者・発行元:AMER INST PHYSICS

    DOI: 10.1063/1.3641982  

    ISSN:0021-8979

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    Epitaxial La2NiMnO6 films were grown on (100)-oriented SrTiO3 and (LaAlO3)(0.3)-(SrAl0.5Ta0.5O3)(0.7) (LSAT) substrates under various growth conditions by pulsed laser deposition. Ferromagnetism and transport properties of B-site-ordered perovskite are greatly influenced by growth conditions. Optimum growth conditions of epitaxial La2NiMnO6 films, which exhibit the ferromagnetism similar to bulk properties, are different for SrTiO3 and LSAT substrates probably due to the difference in surface migration. Since the initial stage of epitaxial growth might vary with the type of substrates, the ordering of Ni and Mn ions is different. Therefore, the ferromagnetism of La2NiMnO6 depends on the epitaxial growth conditions and type of substrates. (C) 2011 American Institute of Physics. [doi:10.1063/1.3641982]

  99. Growth of Single-Crystal Phase Pentacene in Ionic Liquids by Vacuum Deposition 査読有り

    Yoko Takeyama, Shingo Maruyama, Yuji Matsumoto

    CRYSTAL GROWTH & DESIGN 11 (6) 2273-2278 2011年6月

    出版者・発行元:AMER CHEMICAL SOC

    DOI: 10.1021/cg101686q  

    ISSN:1528-7483

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    Here, we propose a new vacuum deposition process with an ionic liquid, and demonstrate that the single-crystal phase of pentacene, which is thermodynamically the most stable phase of its polymorphs, can be easily grown through this process. In this process, pentacene was deposited at a temperature above 363 K directly into an ionic-liquid droplet that had been prepared on a substrate beforehand, and nucleated in the ionic-liquid droplet to form many plate-shape crystals in the single-crystal phase. Even though our process time was just 100 min, the crystal quality of pentacene single-crystal phase, the maximum size of which was as large as 300,mu m, was almost equivalent to that obtained by the conventional solution growth process. The ionic-liquid assisted vacuum deposition, therefore, will become one of the alternative processes for the growth of organic single crystals in vacuum.

  100. Electrochemical Characterization of Pentacene Thin Films in Vacuum with an Ionic Liquid as Electrolyte 査読有り

    Shingo Maruyama, Yoko Takeyama, Yuji Matsumoto

    APPLIED PHYSICS EXPRESS 4 (5) 051602 2011年5月

    出版者・発行元:JAPAN SOC APPLIED PHYSICS

    DOI: 10.1143/APEX.4.051602  

    ISSN:1882-0778

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    We propose a new method for the basic characterization of organic semiconductor properties: an electrochemical impedance analysis with an ionic liquid in vacuum. As a demonstration, we applied this method to the estimation of the acceptor density for c-axis-oriented pentacene films grown on an indium tin oxide substrate. The behavior in the growth of a depletion layer within pentacene could be well understood using the conventional simple capacitance model, and the acceptor density was successfully estimated from the Mott-Schottky plot, typically giving a value of 3.7 x 10(15) cm(-3). (C) 2011 The Japan Society of Applied Physics

  101. Electron Beam Irradiation-Induced Reduction of SnO₂ Deposited on TiO₂(110) Surfaces 査読有り

    Yutaro Komuro, Yuji Matsumoto

    The Journal of Physical Chemistry C 115 (14) 6618-6621 2011年4月14日

    出版者・発行元:None

    DOI: 10.1021/jp111703p  

    ISSN:1932-7447

    eISSN:1932-7455

  102. Electron beam irradiation-induced reduction of Sn on epitaxial rutile SnxTi₁-xO₂ alloy thin films 査読有り

    Yutaro Komuro, Hiroshi Kumigashira, Masaharu Oshima, Yuji Matsumoto

    Thin Solid Films 519 (8) 2555-2558 2011年2月

    出版者・発行元:None

    DOI: 10.1016/j.tsf.2010.11.048  

    ISSN:0040-6090

  103. Modulation of the ferromagnetic insulating phase in Pr0.8Ca0.2MnO3 by Co substitution 査読有り

    T. Harada, I. Ohkubo, M. Lippmaa, Y. Matsumoto, M. Sumiya, H. Koinuma, M. Oshima

    PHYSICA STATUS SOLIDI-RAPID RESEARCH LETTERS 5 (1) 34-36 2011年1月

    出版者・発行元:WILEY-V C H VERLAG GMBH

    DOI: 10.1002/pssr.201004467  

    ISSN:1862-6254

    eISSN:1862-6270

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    Ferromagnetic insulator Pr0.8Ca0.2Mn1-yCoyO3 (0 &lt;= y &lt;= 0.7) thin films were epitaxially grown by pulsed laser deposition on substrates of (LaAlO3)O-3(SrAl0.5Ta0.5O3)(0.7) (100). To probe the ferromagnetic insulator state, the Co content dependences of the structural, magnetic, and transport properties were studied. Variation of lattice constant by the Co substitution is well reproduced considering that divalent and trivalent Co ions substitute for Mn ions at the perovskite B-sites. For 0 &lt;= y &lt;= 0.3, the Curie temperature, saturation magnetization, and magnetoresistance increase with increasing Co content, retaining the insulating properties. Detailed analyses of transport and magnetic properties indicate the contribution of both double exchange and superexchange interactions to the appearance of the ferromagnetic insulating phase. (C) 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

  104. Synthesis and Characterization of Thin Films of a Half-Metallic Oxide, Sr2FeMoO6, by Combinatorial Techniques 査読有り

    Shogo Kadota, Yuji Matsumoto, Takao Sasagawa

    JAPANESE JOURNAL OF APPLIED PHYSICS 50 (1) 01BE13 2011年1月

    出版者・発行元:JAPAN SOC APPLIED PHYSICS

    DOI: 10.1143/JJAP.50.01BE13  

    ISSN:0021-4922

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    The ordered double perovskite oxide, Sr2FeMoO6, has a half-metallic property and is considered as one of the best materials for creating spin-polarized current for next-generation spintronics devices. In order to optimize the fabrication conditions for (001)-oriented single-crystalline Sr2FeMoO6 thin films, a combinatorial pulsed laser deposition (PLD) technique, together with combinatorial (high-throughput) characterization, were carried out. It is found that atmospheric pressure during the deposition affects the formation of secondary phases, thus careful control of this parameter is necessary. On the other hand, substrate temperature affects the electric transport property and surface flatness; better results are obtained at a higher substrate temperature. (C) 2011 The Japan Society of Applied Physics

  105. Electrochemical impedance analysis of electric field dependence of the permittivity of SrTiO3 and TiO2 single crystals 査読有り

    Yuji Matsumoto, Shintaro Takata, Ryohei Tanaka, Atsushi Hachiya

    JOURNAL OF APPLIED PHYSICS 109 (1) 014112 2011年1月

    出版者・発行元:AMER INST PHYSICS

    DOI: 10.1063/1.3530612  

    ISSN:0021-8979

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    Electric field dependence of the permittivity of Nb-doped SrTiO3 (001) (Nb:STO) and Nb-doped TiO2 (110) (Nb:TiO2) were investigated by using an electrochemical impedance spectroscopy method. The plots for Nb: STO could be well fitted to extrapolate the flat-band potential and the donor density, provided that a model of the electric field dependence of the permittivity of STO is incorporated into the conventional Mott-Schottky equation. The constants that represents a degree of the electric field dependence of the permittivity were calculated from the fitting parameters, and they were in good agreement with the reported values for the Nb:STO-based solid-state Schottky junction. In a similar way, the electric field dependence of the permittivity of Nb:TiO2 was revealed but it was not so strong as the case of Nb: STO, which is a basis for the validity of the linear fitting approximation with the conventional Mott-Schottky equation for TiO2. (c) 2011 American Institute of Physics. [doi:10.1063/1.3530612]

  106. Self-Template Growth of Ferroelectric Bi4Ti3O12 Nanoplates via Flux-Mediated Epitaxy with VOx 査読有り

    A. Imai, V. Nagarajan, R. Takahashi, M. Lippmaa, Y. Matsumoto

    CRYSTAL GROWTH & DESIGN 10 (12) 5233-5237 2010年12月

    出版者・発行元:AMER CHEMICAL SOC

    DOI: 10.1021/cg101038z  

    ISSN:1528-7483

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    Flux-mediated epitaxy of self-assembled ferroelectric Bi4Ti3O12 (BIT) nanoplates on SrTiO3 (001) is investigated with vanadium oxide (VOx) as the flux medium It is shown that precoverage of a SrTiO3 (001) substrate with VOx helps to nucleate thin ruffle TiO2 (001) crystallites that act as templates for the subsequent growth of (110)-oriented BIT nanoplates Piezoresponse force microscopy reveals the presence of 90 degrees domain walls even within a single BIT nanoplate similar to BIT bulk single crystals

  107. Chemical trend of Fermi-level shift in transition metal-doped TiO2 films 査読有り

    Yuji Matsumoto, Masao Katayama, Takatoshi Abe, Takeo Ohsawa, Isao Ohkubo, Hiroshi Kumigashira, Masaharu Oshima, Hideomi Koinuma

    JOURNAL OF THE CERAMIC SOCIETY OF JAPAN 118 (1383) 993-996 2010年11月

    出版者・発行元:CERAMIC SOC JAPAN-NIPPON SERAMIKKUSU KYOKAI

    DOI: 10.2109/jcersj2.118.993  

    ISSN:1882-0743

    eISSN:1348-6535

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    The effect of doping a wide range of transition metals (TMs) including V, Cr, Mn, Fe, Co, and Ni into rutile TiO2 films grown on Nb-doped TiO2(110) single-crystal substrates was investigated by photoemission spectroscopy and X-ray absorption spectroscopy. For all TM-doped TiO2 films, the Ti 2p and O is core levels were similarly shifted to lower binding energies with increasing film thickness and the shifts were similarly saturated at a film thickness of about 15 nm. These peak shifts could be interpreted in terms of the Fermi level shift, indicating that dopants trap excess electrons from the Ti 3d band like acceptors. The present systematic data revealed that the magnitude of the saturated Fermi level shift correlates well with the effective charge transfer energy. (C) 2010 The Ceramic Society of Japan. All rights reserved.

  108. Molecular Beam Deposition of Nanoscale Ionic Liquids in Ultrahigh Vacuum 査読有り

    Shingo Maruyama, Yoko Takeyama, Hiroki Taniguchi, Hiroki Fukumoto, Mitsuru Itoh, Hiroshi Kumigashira, Masaharu Oshima, Takakazu Yamamoto, Yuji Matsumoto

    ACS NANO 4 (10) 5946-5952 2010年10月

    出版者・発行元:AMER CHEMICAL SOC

    DOI: 10.1021/nn101036v  

    ISSN:1936-0851

    eISSN:1936-086X

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    We propose a new approach to nanoscience and technology for ionic liquids (ILs): molecular beam deposition of IL in ultrahigh vacuum by using a continuous wave infrared (CW-IR) laser deposition technique. This approach has made it possible to prepare a variety of "nano-IL" with the given composition on the substrate: a nanodroplet, on one hand, the volume of which goes down to 1 aL and, on the other hand, an ultrathin film with a thickness to several 100 nm or less. The result of fractional distillation of a binary mixture of ILs, investigated by nuclear magnetic resonance as well as electrospray ionization time-of-flight mass spectrometry, indicates that this deposition process is based on the thermal evaporation of ILs, and thus this process also can be used as a new purification method of ILs in vacuum. Furthermore, the fabrication of binary mixture droplets of two ILs on the substrate by alternating deposition of two HA was demonstrated; the homogeneity of the composition was confirmed even for one single droplet by high-spatial-resolution Raman spectroscopy.

  109. Device size dependence of resistance switching performance in metal/manganite/metal trilayers 査読有り

    G. Sugano, I. Ohkubo, T. Harada, T. Ohnishi, M. Lippmaa, Y. Matsumoto, H. Koinuma, M. Oshima

    MATERIALS SCIENCE AND ENGINEERING B-ADVANCED FUNCTIONAL SOLID-STATE MATERIALS 173 (1-3) 3-6 2010年10月

    出版者・発行元:ELSEVIER SCIENCE BV

    DOI: 10.1016/j.mseb.2009.11.022  

    ISSN:0921-5107

    eISSN:1873-4944

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    We have fabricated epitaxial Pr(0.8)Ca(0.2)MnO(3) (PCMO) insulator layers sandwiched between Al top electrodes and epitaxial La(0.6)Sr(0.4)MnO(3) bottom electrode layers on (LaAlO(3))(0.3)-(Sr(2)AlTaO(6))(0.7) (100) substrates. Various sizes of metal/insulator/metal device structures were formed by photolithography and Ar ion milling. Device size dependence of Al/PCMO interface resistances was well fitted by series-parallel equivalent circuit, indicating several types of different resistance components exist at the Al/PCMO interfaces. These different resistance components suggest that defects might distribute inhomogeneously at the Al/PCMO interfaces which exhibit the resistance switching. (C) 2009 Elsevier B.V. All rights reserved.

  110. Fabrication and photoelectrochemical properties of La5Ti2MS5O7 (M = Ag, Cu) electrodes 査読有り

    M. Katayama, D. Yokoyama, Y. Maeda, Y. Ozaki, M. Tabata, Y. Matsumoto, A. Ishikawa, J. Kubota, K. Domen

    MATERIALS SCIENCE AND ENGINEERING B-ADVANCED FUNCTIONAL SOLID-STATE MATERIALS 173 (1-3) 275-278 2010年10月

    出版者・発行元:ELSEVIER SCIENCE BV

    DOI: 10.1016/j.mseb.2009.12.021  

    ISSN:0921-5107

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    Electrodes of La5Ti2MS5O7 (M = Ag, Cu) were prepared and photoelectrochemical properties of the electrodes were investigated. Two types of electrode preparation methods were carried out: one was spreading a viscous slurry of the bulk powder on a glass plate coated with fluorine-doped tin oxide, and another was thin film growth by vacuum processes followed by annealing treatment. By the use of vacuum processes, clear and higher photocurrent under visible-light irradiation was observed for both La5Ti2CuS5O7 and La5Ti2AgS5O7. The observed photocurrent was photocathodic, indicating that these materials acted as a p-type semiconductor. La5Ti2MS5O7 are promising materials of a photoelectrode for water splitting under visible-light irradiation. (C) 2009 Elsevier B.V. All rights reserved.

  111. Reduction of nonradiative recombination center for ZnO films grown under Zn-rich conditions by metal organic chemical vapor deposition 査読有り

    Eiji Fujimoto, Kenji Watanabe, Yuji. Matsumoto, Hideomi Koinuma, Masatomo Sumiya

    APPLIED PHYSICS LETTERS 97 (13) 131913 2010年9月

    出版者・発行元:AMER INST PHYSICS

    DOI: 10.1063/1.3492855  

    ISSN:0003-6951

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    ZnO films were grown by metalorganic chemical vapor deposition using the repeated temperature modulation in an H(2) ambient. The crystalline quality, as defined by the full-width at half-maximum of the omega (10 (1) over bar1) reflection, was found to be correlated with the photoluminescence (PL) lifetime at 300 K. The fine structure of the PL spectra for the samples grown under Zn-rich condition at 8 K indicated the higher order (n=2) structure of free exciton A, two electron satellites and phonon-replicas. The internal quantum efficiency and the PL lifetime at 300 K were 5.5% and 2.6 ns, respectively, indicating a reduction in Zn vacancies in the ZnO films. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3492855]

  112. Nonfaceted Growth of (111)-Oriented Epitaxial Alkali-Halide Crystals via an Ionic Liquid Flux in a Vacuum 査読有り

    Shun Kato, Yoko Takeyama, Shingo Maruyama, Yuji Matsumoto

    CRYSTAL GROWTH & DESIGN 10 (8) 3608-3611 2010年8月

    出版者・発行元:AMER CHEMICAL SOC

    DOI: 10.1021/cg100493t  

    ISSN:1528-7483

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    Nonfaceted growth of (111)-oriented epitaxial KBr crystals on sapphire single crystal substrates has been achieved using a novel vacuum deposition method of flux-mediated epitaxy, involving the use of ionic liquids as a flux. It was found that the ionic liquid could act as a flux to promote the growth of KBr at higher growth temperatures and to stabilize its unstable polar (111) face with no faceting of the crystal surface. Even after evaporation of the remaining ionic liquid to remove it from the KBr crystals, the atomically flat (111) surface could be preserved without refaceting.

  113. Epilayer control of photodeposited materials during UV photocatalysis (vol 94, 232901, 2009) 査読有り

    R. Takahashi, M. Katayama, O. Dahl, J. K. Grepstad, Y. Matsumoto, T. Tybell

    APPLIED PHYSICS LETTERS 97 (5) 059903 2010年8月

    出版者・発行元:AMER INST PHYSICS

    DOI: 10.1063/1.3449136  

    ISSN:0003-6951

  114. Vacuum and Pressured Combinatorial Processings for Exploration of Environmental Catalysts 査読有り

    Hideomi Koinuma, Kenji Itaka, Yuji Matsumoto, Yasuhiko Yoshida, Shunichi Aikawa, Kazuhiko Takeuchi

    TOPICS IN CATALYSIS 53 (1-2) 35-39 2010年2月

    出版者・発行元:SPRINGER/PLENUM PUBLISHERS

    DOI: 10.1007/s11244-009-9436-5  

    ISSN:1022-5528

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    Two types of combinatorial chemical reactors have been developed for high-throughput experimentation of catalysts that attract much interest from global environmental viewpoints. The high vacuum combinatorial laser MBE system was applied to the preparation of thin film library of TiO(2) with its film thickness gradually increased, which resulted in the discovery of new phenomenon indicating a quantum size effect in TiO(2) photo-catalysis. The combinatorial autoclave reactor was made to explore new catalysts and optimum reaction conditions efficiently for alternating CO(2) copolymerization with epoxide (oxirane) to form bio-degradable polycarbonates. Some preliminary results are reported on the CO(2) copolymerization with propylene oxide, as a means of CO(2) fixation into chemically useful material.

  115. Deposition of Amorphous Zinc Indium Tin Oxide and Indium Tin Oxide Films on Flexible Poly(ether sulfone) Substrate Using RF Magnetron Co-sputtering System 査読有り

    Gi-Seok Heo, Yuji Matsumoto, In-Gi Gim, Jong-Woon Park, Gwang-Young Kim, Tae-Won Kim

    JAPANESE JOURNAL OF APPLIED PHYSICS 49 (3) 035801 2010年

    出版者・発行元:JAPAN SOC APPLIED PHYSICS

    DOI: 10.1143/JJAP.49.035801  

    ISSN:0021-4922

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    Zn-In-Sn-O (ZITO) and In-Sn-O (ITO) thin films were deposited at room temperature on poly( ether sulfone) ( PES) substrates using a combinatorial rf magnetron co-sputtering system. The cationic contents of the films were varied using a compositionally combinatorial technique. The average optical transmittance of the ZITO films was &gt;80% in the visible region. The ZITO films showed an amorphous phase regardless of the zinc content. A minimum resistivity of 4.1 x 10(-4) Omega.cm was obtained at a zinc content of 8.9 at.% [Zn/(In + Zn + Sn)]. The amorphous ZITO films deposited on flexible substrates had good mechanical durability against external dynamic stress, as measured using a bending test. Overall, the characteristics of the ZITO films were comparable or superior to those of the amorphous ITO films, and thus ZITO films may serve as a viable, low-cost alternative for electrode applications in flexible organic light-emitting diodes or organic solar cells. (C) 2010 The Japan Society of Applied Physics

  116. Photocatalytic Synthesis of Silver-Oxide Clathrate Ag7O8NO3 査読有り

    R. Tanaka, S. Takata, M. Katayama, R. Takahashi, J. K. Grepstad, T. Tybell, Y. Matsumoto

    JOURNAL OF THE ELECTROCHEMICAL SOCIETY 157 (12) E181-E183 2010年

    出版者・発行元:ELECTROCHEMICAL SOC INC

    DOI: 10.1149/1.3503581  

    ISSN:0013-4651

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    Photocatalytic synthesis of silver-oxide clathrate Ag7O8NO3 was investigated. The process is based on photocatalytic enhanced oxidation of Ag+ in a AgNO3 aqueous solution using a titanate-based photocatalyst (SrTiO3) single crystal. By doping the crystal with Nb or La, the photocatalytic production of Ag7O8NO3 is enhanced even for relatively low concentrations of AgNO3 aqueous solutions and more with higher Nb doping. This photocatalytic reaction can be understood in terms of selectivity of the oxidation reaction, favoring generation of O-2 or Ag7O8NO3, with the Nb doping as well as the concentration of the AgNO3 aqueous solution having strong impact on the reaction selectivity. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3503581] All rights reserved.

  117. Transparent conducting amorphous Zn-In-Sn-O anode for flexible organic light-emitting diodes 査読有り

    Gi-Seok Heo, Yuji Matsumoto, In-Gi Gim, Hyun-Kee Lee, Jong-Woon Park, Tae-Won Kim

    SOLID STATE COMMUNICATIONS 150 (3-4) 223-226 2010年1月

    出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD

    DOI: 10.1016/j.ssc.2009.10.042  

    ISSN:0038-1098

    eISSN:1879-2766

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    Amorphous Zn-In-Sn-O (ZITO) films are grown by an rf magnetron cosputtering system from ceramic oxide targets of ZnO and ITO onto a flexible polyether sulfone (PES) substrate. The films exhibit resistivity as low as 1.22 x 10(-3) Omega cm and optical transparency comparable to greater than that of Sn-doped indium oxide (ITO) films. The amorphous ZITO films have good mechanical durability compared to ITO films against the external dynamic stress measured by the bending tester. The deposited ZITO film has been used as a transparent anode in fabrication of the flexible organic light-emitting diode (OLED) by the cluster organic evaporator system. The amorphous ZITO anode-based flexible OLED shows comparable or superior current density and luminance characteristics compared to that of the amorphous ITO-based OLED. (C) 2009 Published by Elsevier Ltd

  118. Combinatorial fabrication and magnetic properties of homoepitaxial Co and Li co-doped NiO thin-film nanostructures 査読有り

    U. S. Joshi, K. Itaka, Y. Matsumoto, H. Koinuma

    JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS 321 (21) 3595-3599 2009年11月

    出版者・発行元:ELSEVIER SCIENCE BV

    DOI: 10.1016/j.jmmm.2009.06.081  

    ISSN:0304-8853

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    Magnetic properties of nanostructured epitaxial thin layers of a series of Co and Li co-doped NiO on MgO(100) substrate with NiO buffer layer have been investigated. Thin films were synthesized by combinatorial laser molecular beam epitaxy (CLMBE) in the continuous binary composition spread approach. Large and linear variation of x was achieved in the growth of Co(x)Li(0.2)Ni(0.8-x)O, onto 9 mm of single substrate. Homoepitaxial growth with smooth surface morphology was confirmed by grazing incidence X-ray diffraction (GIXRD) and atomic force microscopy (AFM). Linear decrease in the band gap and optical transparency was observed with increasing cobalt concentration. The magneto-optical Kerr effect revealed a strong photon energy dependency with negative Kerr rotation for all the Co-concentrations in the film, suggesting intra-valence charge transfer (IVCT) between low spin state Co(2+) with host Ni(2+). Ferromagnetic (FM)-like ordering was observed at low temperatures, while antiferromagnetism predominates at room temperature in the Co and Li co-doped nickel oxide epitaxial films. (C) 2009 Elsevier B.V. All rights reserved.

  119. Fabrication of cosputtered Zn-In-Sn-O films and their applications to organic light-emitting diodes 査読有り

    Gi-Seok Heo, Yuji Matsumoto, In-Gi Gim, Jong-Woon Park, Kwang-Young Kim, Tae-Won Kim

    SOLID STATE COMMUNICATIONS 149 (41-42) 1731-1734 2009年11月

    出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD

    DOI: 10.1016/j.ssc.2009.07.050  

    ISSN:0038-1098

    eISSN:1879-2766

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    Zn-In-Sn-O (ZITO) films have been grown by rf magnetron cosputtering system from ceramic oxide targets of ZnO and ITO onto glass substrate. X-ray diffraction analysis shows that the microstructure is amorphous below the substrate temperature of 250 degrees C. The films exhibit sheet resistance as low as 16.7 Omega/square and optical transparency comparable to grater than that of Sn-doped indium oxide (ITO) films. The work function ranged 5.05-5.19 eV, which is a higher work function compared to [TO (4.7 eV). The fabricated ZITO films are used in fabrication of organic light-emitting diodes (OLEDs). The ZITO anode with the zinc content of 12.5 at.% [Zn/(Zn + In + Sn)] fabricated at 250 degrees C-based OLED shows lower turn-on voltage and higher current density compared to that of ITO-based control device. (C) 2009 Elsevier Ltd. All rights reserved.

  120. Anisotropy of magnetization-induced surface optical second harmonic generation from Co doped rutile TiO2 査読有り

    R. Watanabe, M. Tamura, Y. Yahata, G. Mizutani, T. Suzuki, Y. Segawa, Y. Matsumoto, Y. Yamamoto, H. Koinuma

    APPLIED SURFACE SCIENCE 256 (4) 1092-1095 2009年11月

    出版者・発行元:ELSEVIER SCIENCE BV

    DOI: 10.1016/j.apsusc.2009.05.073  

    ISSN:0169-4332

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    We have investigated the surface magnetization anisotropy of 5 at% Co doped rutile TiO2 (1 1 0) using magnetization-induced optical second harmonic generation (MSHG) in the longitudinal Kerr configuration with an incident beam angle of 4 degrees. The MSH intensity pattern from the Co: TiO2 without surface Co clusters showed two anisotropic lobes at the second harmonic photon energy of 2(sic)omega: 3.13 eV. Since MSH intensity is proportional to surface magnetization, the result indicates an anisotropy of the surface magnetization of Co: rutile TiO2(1 1 0). This confirms the possibility that 5 at% Co: rutile TiO2(1 1 0) is a ferromagnetic dilutemagnetic semiconductor at its surface, as proposed in our previous paper. (C) 2009 Elsevier B.V. All rights reserved.

  121. Improved wettability of Sn-based solder over the Cu60Zr30Ti10 bulk metallic glass surface 査読有り

    A. Imai, M. Katayama, S. Maruyama, H. Nishikawa, T. Wada, H. Kimura, M. Fukuhara, T. Takemoto, A. Inoue, Y. Matsumoto

    JOURNAL OF MATERIALS RESEARCH 24 (9) 2931-2934 2009年9月

    出版者・発行元:CAMBRIDGE UNIV PRESS

    DOI: 10.1557/JMR.2009.0343  

    ISSN:0884-2914

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    The wettability of Pb-free Sn-based solder over the Cu-based Cu60Zr30Ti10 bulk metallic glass surface was investigated. We observed that the as-polished surface was nonwetting for the solder, which was due to the surface oxide layer of ZrOx formed in air. After complete removal of the oxide layer, a thin layer of Ag was deposited on the clean Cu60Zr30Ti10 surface. The Ag-covered Cu60Zr30Ti10 surface showed relatively high resistivity to the reoxidation even in air, and thus the wettability of the Cu60Zr30Ti10 surface for the Sn-based solder was greatly improved.

  122. Epilayer control of photodeposited materials during UV photocatalysis 査読有り

    R. Takahashi, M. Katayama, O. Dahl, J. K. Grepstad, Y. Matsumoto, T. Tybell

    APPLIED PHYSICS LETTERS 94 (23) 232901 2009年6月

    出版者・発行元:AMER INST PHYSICS

    DOI: 10.1063/1.3151820  

    ISSN:0003-6951

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    Epilayer control of photoassisted oxidation and reduction on the ferroelectric PbTiO(3) polar surface was investigated. Photo-oxidation of a AgNO(3) electrolyte resulting in formation of Ag(7)NO(11) particles was observed on the PbTiO(3)/Nb:SrTiO(3) film surface; whereas PbTiO(3)/SrRuO(3)/SrTiO(3) leads to AgNO(3) reduction under UV illumination. The oxidation reaction resulting in the formation of Ag(7)NO(11) is explained in terms of a rectifying interface between PbTiO(3) and Nb:SrTiO(3), controlling the charge transport during UV photocatalysis.

  123. Electronic structure characterization of La2NiMnO6 epitaxial thin films using synchrotron-radiation photoelectron spectroscopy and optical spectroscopy 査読有り

    M. Kitamura, I. Ohkubo, M. Matsunami, K. Horiba, H. Kumigashira, Y. Matsumoto, H. Koinuma, M. Oshima

    APPLIED PHYSICS LETTERS 94 (26) 262503 2009年6月

    出版者・発行元:AMER INST PHYSICS

    DOI: 10.1063/1.3159826  

    ISSN:0003-6951

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    Electronic structures of La2NiMnO6 epitaxial films are characterized using synchrotron-radiation photoelectron spectroscopy and optical spectroscopy. X-ray absorption spectra reveal that the valence states of Ni2+ and Mn4+ are dominant. The electronic structure at the valence band maximum is mainly derived from the Mn 3d state. The conduction band minimum is composed mostly of the Mn 3d-O 2p hybridized state. The optical gap is estimated to be about 1.5 eV based on the optical conductivity derived from optical spectra.

  124. Hetero-Epitaxial Growth of ZnO Film by Temperature-Modulated Metalorganic Chemical Vapor Deposition 査読有り

    Eiji Fujimoto, Masatomo Sumiya, Tsuyoshi Ohnishi, Kenji Watanabe, Mikk Lippmaa, Yuji Matsumoto, Hideomi Koinuma

    APPLIED PHYSICS EXPRESS 2 (4) 045502 2009年4月

    出版者・発行元:JAPAN SOCIETY APPLIED PHYSICS

    DOI: 10.1143/APEX.2.045502  

    ISSN:1882-0778

    eISSN:1882-0786

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    ZnO films were fabricated by metalorganic chemical vapor deposition while a laser substrate heating system was used to rapidly cycle the sample temperature. When a hydrogen gas atmosphere was used together with the temperature modulation, ZnO films deposited from diethyl-zinc and oxygen exhibited oxygen-face polarity and a smooth surface. The quality of ZnO films was good enough to observe phonon replicas corresponding to the transition from donor-bound to free exciton in the temperature dependence of photoluminescence. The growth of ZnO film is discussed in relation to the combined effect of growth temperature modulation and the hydrogen atmosphere. (C) 2009 The Japan Society of Applied Physics

  125. Ferromagnetic properties of epitaxial La2NiMnO6 thin films grown by pulsed laser deposition 査読有り

    M. Kitamura, I. Ohkubo, M. Kubota, Y. Matsumoto, H. Koinuma, M. Oshima

    APPLIED PHYSICS LETTERS 94 (13) 132506 2009年3月

    出版者・発行元:AMER INST PHYSICS

    DOI: 10.1063/1.3111436  

    ISSN:0003-6951

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    La2NiMnO6 (LNMO) thin films were fabricated on (100) oriented SrTiO3 single crystal substrates by pulsed laser deposition method. The film growth conditions were found to significantly affect the magnetic moment and ferromagnetic transition temperature of LNMO films. Epitaxial LNMO films exhibiting the ferromagnetism equivalent to that of bulk polycrystal were grown only in such a narrow region of growth temperature and oxygen pressure that stabilized Ni2+-O-Mn4+ superexchange ferromagnetic interaction. Out of this narrow region, the ferromagnetism is significantly suppressed by the appearance of secondary phases, locally disordered Ni and Mn ions, and oxygen vacancies.

  126. In situ Auger Electron Spectroscopy Study of the Pentacene Film Grown on the SrTiO3(001) Surface 査読有り

    Kozue Hotozuka, Masao Katayama, Yuji Matsumoto

    JAPANESE JOURNAL OF APPLIED PHYSICS 48 (2) 020207 2009年2月

    出版者・発行元:JAPAN SOC APPLIED PHYSICS

    DOI: 10.1143/JJAP.48.020207  

    ISSN:0021-4922

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    We have investigated the growth and photodecom position of the pentacene ultrathin film grown on the TiO2-terminated SrTiO3(001) single crystal substrate by in situ Auger electron spectroscopy (AES) and ex situ atomic force microscopy (AFM). The careful analyses of AES and AFM data have revealed that the AES intensities of C(KLL) in the growth of the pentacene were to some extent larger than those in its photodecomposition, for the coverage of pentacene islands estimated by AFM. This result supports the existence of adsorbed-like pentacene precursors before the photodecomposition as was proposed in our previous report. (C) 2009 The Japan Society of Applied Physics

  127. Magnetization-induced optical second harmonic generation from the surface of Co-doped rutile TiO2(110) 査読有り

    R. Watanabe, M. Yuasa, Y. Yahata, G. Mizutani, T. Suzuki, Y. Segawa, Y. Matsumoto, Y. Yamamoto, H. Koinuma

    SURFACE AND INTERFACE ANALYSIS 40 (13) 1692-1695 2008年12月

    出版者・発行元:WILEY-BLACKWELL

    DOI: 10.1002/sia.2907  

    ISSN:0142-2421

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    We have investigated the surface magnetism of 5 at% Co-doped rutile TiO2(110) using magnetization-induced optical second harmonic generation (MSHG) in the longitudinal Kerr configuration with the incident beam angle of 4 degrees. MSHG is observed at both 2h omega = 2.33 eV and 2h omega = 4.20 eV. MSH intensity showed a hysteresis as a function of the external magnetic field for the second harmonic photon energy of 2h omega = 4.20 eV at which the absorption length limits the MSHG origin to the surface layer of 10 nm due to the TiO2 bulk. Since 5 at% Co: TiO2(110) is judged to have no metallic Co near the top surface by XPS, the hysteresis is attributed to a carrier-induced ferromagnetism at the surface of this material. Copyright (C) 2008 John Wiley & Sons, Ltd.

  128. Trap-controlled space-charge-limited current mechanism in resistance switching at Al/Pr(0.7)Ca(0.3)MnO(3) interface 査読有り

    T. Harada, I. Ohkubo, K. Tsubouchi, H. Kumigashira, T. Ohnishi, M. Lippmaa, Y. Matsumoto, H. Koinuma, M. Oshima

    APPLIED PHYSICS LETTERS 92 (22) 222113 2008年6月

    出版者・発行元:AMER INST PHYSICS

    DOI: 10.1063/1.2938049  

    ISSN:0003-6951

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    Well-defined metal-insulator-metal trilayered structures composed of epitaxial Pr(0.7)Ca(0.3)MnO(3) insulator layers, epitaxial LaNiO(3) bottom electrodes, and Al metal top electrodes were fabricated on LaAlO(3) (100) substrates. The I-V characteristics of the trilayer structures show electric-field-induced resistance switching. The resistance switching ratio of the heterostructures was up to 100 when positive and negative pulsed voltages were applied. Detailed I-V analysis indicates the importance of both trap-controlled space-charge-limited current and Poole-Frenkel effect in resistance switching at Al/Pr(0.7)Ca(0.3)MnO(3) interfaces. (C) 2008 American Institute of Physics.

  129. Epitaxial growth and surface metallic nature of LaNiO3 thin films 査読有り

    K. Tsubouchi, I. Ohkubo, H. Kumigashira, Y. Matsumoto, T. Ohnishi, M. Lippmaa, H. Koinuma, M. Oshima

    APPLIED PHYSICS LETTERS 92 (26) 262109 2008年6月

    出版者・発行元:AMER INST PHYSICS

    DOI: 10.1063/1.2955534  

    ISSN:0003-6951

    eISSN:1077-3118

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    In situ epitaxial growth control of LaNiO3 (LNO) films at high oxygen pressure has been successfully achieved using a combination of pulsed laser deposition and high-pressure reflection high-energy electron diffraction (RHEED). RHEED oscillations, indicative of epitaxial layer-by-layer growth, were clearly observed during LNO deposition under optimal conditions. The film surfaces were composed of atomically flat terraces and steps. Detailed photoelectron spectroscopy analysis of LNO grown at the optimal oxygen pressure revealed that Ni ions assume a uniform Ni3+ high-valence state and that the resultant metallic properties are preserved even at the surface and in the interface region between LNO and the LaAlO3 substrate. (C) 2008 American Institute of Physics.

  130. Photochemical switching of ultrathin PbTiO3 films 査読有り

    R. Takahashi, J. K. Grepstad, T. Tybell, Y. Matsumoto

    APPLIED PHYSICS LETTERS 92 (11) 112901 2008年3月

    出版者・発行元:AMER INST PHYSICS

    DOI: 10.1063/1.2890485  

    ISSN:0003-6951

    eISSN:1077-3118

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    The ferroelectric domain ground state of PbTiO3 thin films on Nb:SrTiO3 substrates has been studied as a function of film thickness. High resolution linear Q(x) x-ray diffraction profiles were recorded in order to probe the presence of stripe domains, which were invariably observed for as-grown samples. After photochemical treatment, films thinner than 50 unit cells were switched to a monodomain state that could be reversed upon subsequent annealing. The stripe-domain state is linked to a Q(x) modulation of the Q(z) parameter in the reciprocal space, which disappears upon switching. (c) 2008 American Institute of Physics.

  131. High quality anatase TiO(2) film: Field-effect transistor based on anatase TiO(2) 査読有り

    Masao Katayama, Shinya Ikesaka, Jun Kuwano, Hideomi Koinuma, Yuji Matsumoto

    APPLIED PHYSICS LETTERS 92 (13) 132107 2008年3月

    出版者・発行元:AMER INST PHYSICS

    DOI: 10.1063/1.2906361  

    ISSN:0003-6951

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    We proposed an oxygen modulation method for the growth of high crystalline and insulative anatase films. The cycle of deposition under low oxygen pressure and annealing under high oxygen pressure was repeated every 1 nm thick growth. The sharp reflection high-energy electron diffraction pattern and step-and-terrace surface morphology confirmed high crystallinity of the obtained anatase film; the resistivity reached as high as 1.8 M Omega cm. As a result, the present anatase film exhibited high performance in a field-effect transistor as an active channel. On-to-off current ratio and field-effect mobility exceeded 10(5) and 0.3 cm(2)/V s, respectively. (C) 2008 American Institute of Physics.

  132. Composition-spread thin films of pentacene and 6,13-pentacenequinone fabricated by using continuous-wave laser molecular beam epitaxy 査読有り

    Seiichiro Yaginuma, Kenji Itaka, Yuji Matsumoto, Tsuyoshi Ohnishi, Mikk Lippmaa, Takahiro Nagata, Toyohiro Chikyow, Hideomi Koinuma

    APPLIED SURFACE SCIENCE 254 (8) 2336-2341 2008年2月

    出版者・発行元:ELSEVIER SCIENCE BV

    DOI: 10.1016/j.apsusc.2007.09.052  

    ISSN:0169-4332

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    Synthesis of continuous composition-spread (CCS) thin films is widely recognized in combinatorial material science as a powerful technique for rapidly investigating the properties of new functional materials. However, there are very few reports of CCS organic thin films due to the fact that the thermal evaporation method with Knudsen cells, which is commonly used to fabricate organic thin films in vacuum, does not offer the necessary level of deposition rate control as, for example, does pulsed laser deposition (PLD). We have successfully fabricated organic CCS thin films of pentacene and 6,13-pentacenequinone by continuous-wave laser molecular beam epitaxy (CWL-MBE), which we developed as a new fabrication method for organic thin films. The composition-spread films were characterized systematically by ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, atomic force microscopy, and two-probe conductivity measurements. The present work brings the advantages of high-throughput parallel synthesis and systematic characterization to the field of organic electronics, allowing for quick exploration and rapid optimization of organic functional materials and devices. (c) 2007 Published by Elsevier B.V.

  133. Field-induced resistance switching at metal/perovskite manganese oxide interface 査読有り

    I. Ohkubo, K. Tsubouchi, T. Harada, H. Kumigashira, K. Itaka, Y. Matsumoto, T. Ohnishi, M. Lippmaa, H. Koinuma, M. Oshima

    MATERIALS SCIENCE AND ENGINEERING B-ADVANCED FUNCTIONAL SOLID-STATE MATERIALS 148 (1-3) 13-15 2008年2月

    出版者・発行元:ELSEVIER SCIENCE BV

    DOI: 10.1016/j.mseb.2007.09.004  

    ISSN:0921-5107

    eISSN:1873-4944

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    Planar type metal/insulator/metal structures composed of an epitaxial perovskite manganese oxide layer and various metal electrodes Were prepared for electric-field-induced resistance switching. Only the electrode pairs including Al show good resistance switching and the switching ratio reaches its maximum of 1000. This resistance switching occurs around the interface between Al electrodes and epitaxial perlovskite manganese oxide thin films. (C) 2007 Elsevier B.V. All rights reserved.

  134. Modification of reflection high-energy electron diffraction system for in situ monitoring of oxide epitaxy at high oxygen pressure 査読有り

    K. Tsubouchi, I. Ohkubo, T. Harada, H. Kumigashira, Y. Matsumoto, T. Ohnishi, M. Lippmaa, H. Koinuma, M. Oshima

    MATERIALS SCIENCE AND ENGINEERING B-ADVANCED FUNCTIONAL SOLID-STATE MATERIALS 148 (1-3) 16-18 2008年2月

    出版者・発行元:ELSEVIER SCIENCE BV

    DOI: 10.1016/j.mseb.2007.09.005  

    ISSN:0921-5107

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    We have developed a modified single-stage differentially pumped RHEED system for in situ monitoring of oxide epitaxial growth at high oxygen pressure. This modification enables us to operate the RHEED system up to oxygen pressure of 100 mTorr. RHEED intensity oscillations indicative of the layer-by-layer growth were clearly observed during LaNiO(3) epitaxial growth at 30 mTorr of pure oxygen ambient. LaNiO(3) epitaxial thin films showed both atomically flat surfaces and low resistivity, suggesting that the operative oxygen pressure was high enough to epitaxially grow oxide films - under optimum conditions. (C) 2007 Elsevier B.V. All rights reserved.

  135. Epitaxial insulator for bottom-gate field-effect devices based on TiO2 査読有り

    Masao Katayama, Hideomi Koinuma, Yuji Matsumoto

    MATERIALS SCIENCE AND ENGINEERING B-ADVANCED FUNCTIONAL SOLID-STATE MATERIALS 148 (1-3) 19-21 2008年2月

    出版者・発行元:ELSEVIER SCIENCE BV

    DOI: 10.1016/j.mseb.2007.09.050  

    ISSN:0921-5107

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    Field-effect devices with bottom-gate structure based on anatase TiO2 active channels were fabricated. The key factor to achieve this was the quality of epitaxial insulator layers, viz.; the insulating property and their crystallinity, because they work not only as a well insulator for field-effect devices but also as a template for the subsequent growth of epitaxial active layers. Our devices showed typical transistor actions. On-to-off current ratio exceeded 10(4) and the field effect mobility of 0.04 cm(2)/V S were obtained. Interestingly, the device characteristics were found to be sensitive to ambient and light, suggesting their potential for manipulating the fruitful TiO2 surface functions by tuning the gate voltage. (C) 2007 Elsevier B.V. All rights reserved.

  136. Electrode dependence and film resistivity electric-field-induced resistance-switching in epitaxial NiO films effect in the phenomena 査読有り

    T. Ishiharaa, I. Ohkubo, K. Tsubouchi, H. Kumigashira, U. S. Joshi, Y. Matsumoto, H. Koinuma, M. Oshima

    MATERIALS SCIENCE AND ENGINEERING B-ADVANCED FUNCTIONAL SOLID-STATE MATERIALS 148 (1-3) 40-42 2008年2月

    出版者・発行元:ELSEVIER SCIENCE BV

    DOI: 10.1016/j.mseb.2007.09.073  

    ISSN:0921-5107

    eISSN:1873-4944

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    We have investigated the electric-field-induced resistance-switching phenomena using Al and Ni electrodes on epitaxial NiO films with various resistivities. For excluding effects due to grain boundaries and roughness of NiO-electrode interfaces, epitaxial NiO films having atomically flat surfaces and high crystalline quality were fabricated by pulsed laser deposition. It is suggested that the resistance switching occurs around Al-NiO interfaces since only the electrode pairs including Al exhibit the resistance switching. Furthermore, this resistance switching strongly depends on NiO film resistivities, indicating that carrier density is also an important factor for resistance switching. (C) 2007 Elsevier B.V. All rights reserved.

  137. Brazing of Cu with Pd-based metallic glass filler 査読有り

    Takeshi Terajima, Kazuhiro Nakata, Yuji Matsumoto, Wei Zhang, Hisamichi Kimura, Akihisa Inoue

    MATERIALS SCIENCE AND ENGINEERING B-ADVANCED FUNCTIONAL SOLID-STATE MATERIALS 148 (1-3) 128-131 2008年2月

    出版者・発行元:ELSEVIER SCIENCE BV

    DOI: 10.1016/j.mseb.2007.09.084  

    ISSN:0921-5107

    eISSN:1873-4944

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    Metallic glass has several unique properties, including high mechanical strength, small solidification shrinkage, small elastic modulus and supercooling state, all of which are well suited as a residual stress buffer for metal and ceramic joining In the present preliminary study, we demonstrated brazing of Cu rods with Pd40Cu30Ni10P20 metallic glass filler. The brazing was carried out at 873 K for 1 min in a vacuum atmosphere (1 x 10(-3) Pa), and then the specimens were quenched at the rate of 30 K/s by blowing He. The metallic glass brazing of Cu using Pd40Cu30Ni10P20 filler was successful, with. the exception that several voids remained in the filler. According to micro-focused X-ray diffraction, no diffraction patterns were observed at both the center of the Pd40Cu30Ni10P20 filler and the Cu/Pd40Cu30Ni10P20 interface. The result showed that the Cu specimens were joined with Pd40Cu30Ni10P20 filler in the glassy state. The tensile fracture strength of the brazed specimens ranged from 20 to 250 MPa. The crack extension from the voids in the Pd40Cu30Ni10P20 filler may have caused the results to be uneven and very low compared to the strength of Pd-based bulk metallic glass. (C) 2007 Elsevier B.V. All rights reserved.

  138. In situ analysis of the thermal behavior in the Zr-based multi-component metallic thin film by pulsed laser deposition combined with UHV-laser microscope system 査読有り

    Yuji Matsumoto, Miki Hiraoka, Masao Katayama, Seiichi Hata, Mikio Fukuhara, Takeshi Wada, Hisamichi Kimura, Akihisa Inoue

    MATERIALS SCIENCE AND ENGINEERING B-ADVANCED FUNCTIONAL SOLID-STATE MATERIALS 148 (1-3) 179-182 2008年2月

    出版者・発行元:ELSEVIER SCIENCE BV

    DOI: 10.1016/j.mseb.2007.09.049  

    ISSN:0921-5107

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    The thermal behavior of the Zr-based multi-component metallic thin films was investigated under an atmospheric N-2 condition by using pulsed laser deposition (PLD)-combined with in situ laser microscope (LM) system. The Zr-based multi-component metallic thin films were prepared in amorphous by PLD with a stoichiometric target of the Zr-based metallic glass. By comprehensive study with ex situ analyses such as XRD, SEM and EPMA techniques, it was found that the gradual formation of Zr2Ni alloy particles occurred above 500 degrees C, and subsequently the inhomogeneous contrast, probably owing to the partial formation of ZrO2 on the film surface appeared at high temperature. (C) 2007 Elsevier B.V. All rights reserved.

  139. Molecular layer-by-layer growth of C-60 thin films by continuous-wave infrared laser deposition 査読有り

    Seiichiro Yaginuma, Kenji Itaka, Masamitsu Haemori, Masao Katayama, Keiji Ueno, Tsuyoshi Ohnishi, Mikk Lippmaa, Yuji Matsumoto, Hideomi Koinuma

    APPLIED PHYSICS EXPRESS 1 (1) 015005 2008年1月

    出版者・発行元:JAPAN SOC APPLIED PHYSICS

    DOI: 10.1143/APEX.1.015005  

    ISSN:1882-0778

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    The observation of reflection high energy electron diffraction (RHEED) oscillations has been proved to be a key to open the nano-world of materials, since it definitely verifies that the film growth proceeds in layer-by-layer mode with each layer thickness controllable by simply counting the number of oscillations. This enabled the fabrication of nano-engineered hetero-junctions and devices as commonly practiced for conventional semiconductors and metals. Here we report on the first observation of clear RHEED intensity oscillation in thin film fabrication of pi-conjugated molecular solid. The observation has been achieved by coupling a novel deposition method using a continuous-wave infrared laser for evaporation and a high sensitive RHEED detector, in addition to the combinatorial optimization of film deposition parameters that facilitated our preceding first success in the layer-by-layer growth of oxide thin films. Some details of system design and experimental conditions are presented to discuss the key factors for atomically controlled film growth of molecular solids. (C) 2008 The Japan Society of Applied Physics.

  140. Direct observation of vortex lattice in Bi2Sr2CaCu2O8+delta by low temperature STM/STS 査読有り

    Fukuo Noritaka, Mashima Hideki, Hitosugi Taro, Uchida Satoshi, Shimoyama Jun-ichi, Kishio Kohji, Matsumoto Yuji, Hasegawa Tetsuya

    PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS 460 734-735 2007年9月1日

    DOI: 10.1016/j.physc.2007.03.157  

    ISSN:0921-4534

  141. Anomalous thickness and dopant effects on photochemical deposition of Ag on epitaxial TiO2(110)/Nb : TiO2(110) heterostructures 査読有り

    T. Abe, T. Ohsawa, M. Katayama, H. Koinuma, Y. Matsumoto

    APPLIED PHYSICS LETTERS 91 (6) 061928 2007年8月

    出版者・発行元:AMER INST PHYSICS

    DOI: 10.1063/1.2769937  

    ISSN:0003-6951

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    The authors have found anomalous thickness and dopant effects on photochemical deposition of Ag on the epitaxial heterostructures of TiO2(110) and V:TiO2(110)/Nb:TiO2(110). The photodeposition of Ag on TiO2(110)/Nb:TiO2(110) is limited to a specific film thickness region of about 5 nm and the V doping is found to enhance the photoactivity, irrespective of the film thickness, on V:TiO2(110)/Nb:TiO2(110). They have also found that the film thickness for maximum photoactivity depends on the wavelength of the irradiated light.

  142. High-throughput characterization of metal electrode performance for electric-field-induced resistance switching in metal/Pr0.7Ca0.3MnO3/metal structures 査読有り

    Kenta Tsubouchi, Isao Ohkubo, Hiroshi Kumigashira, Masaharu Oshima, Yuji Matsumoto, Kenji Itaka, Tsuyoshi Ohnishi, Mikk Lippmaa, Hideomi Koinuma

    ADVANCED MATERIALS 19 (13) 1711-+ 2007年7月

    出版者・発行元:WILEY-V C H VERLAG GMBH

    DOI: 10.1002/adma.200601957  

    ISSN:0935-9648

    eISSN:1521-4095

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    High-throughput exploration of electrode materials is demonstrated with an epitaxial thin-film device to determine the appropriate electrode materials for a resistance random access memory. In I-V measurements, only electrode pairs containing Al showed resistance switching (see figure). The disappearance of switching in the fourprobe measurements suggests that switching occurs near the interface of the Al electrode and the Pr0.7Ca0.3MnO3 film.

  143. Photodecomposition of pentacene films on atomically controlled SrTiO3(001) surfaces 査読有り

    Yuji Matsumoto, Hideomi Koinuma, Takeo Ohsawa

    JOURNAL OF PHYSICAL CHEMISTRY C 111 (28) 10523-10527 2007年7月

    出版者・発行元:AMER CHEMICAL SOC

    DOI: 10.1021/jp072365c  

    ISSN:1932-7447

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    Photodecomposition of pentacene films grown on the atomically controlled SrTiO3(001) (STO) surfaces was investigated by atomic force microscopy. The photodecomposition was found to occur only when the coverage of the pentacene film was less than 1 ML on the TiO2-terminated STO(001). When the oxygen adsorption is a rate-limiting step, the decomposition rate is nearly proportional to the surface area uncovered with pentacene island, while at the last stage of the decomposition it is in proportion not to the coverage of the pentacene islands but to the perimeter of the pentacene islands. The SrO-terminated STO(001) surface exhibits very little activity in the photodecomposition of the pentacene. The exponential decay of the rate constant with the SrO coverage suggests that it is attributed to some chemical effect such as the formation of Sr hydroxide at the SrO-terminated surface.

  144. Inorganic impurity effect on the photoinduced hydrophilic conversion on ultrasmooth SrTiO3 and TiO2 single crystal surfaces 査読有り

    Masao Katayama, Takayuki Miyakawa, Takeo Ohsawa, Jun Kuwano, Hideomi Koinuma, Yuji Matsumoto

    JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS & EXPRESS LETTERS 46 (20-24) L562-L564 2007年6月

    出版者・発行元:INST PURE APPLIED PHYSICS

    DOI: 10.1143/JJAP.46.L562  

    ISSN:0021-4922

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    We report the effect of inorganic impurities on the photoinduced hydrophilic conversion on ultrasmooth SrTiO3 and TiO2 single crystal surfaces. A water droplet became well spread over on a TiO2-terminated SrTiO3(100) surface after UV irradiation, whereas it remained beaded on a SrO-terminated SrTiO3(100) surfaces. ZnO and CuO impurities deposited onto a rutile TiO2(110) surfaces were found to suppress the hydrophilic conversion with increasing amounts of ZnO and CuO. No hydrophilicity characteristic of TiO2 was observed after UV irradiation at a nominal impurity thickness of only 5 angstrom, indicating that the surface-exposed atomic layer plays a crucial role in photoinduced hydrophilic conversion.

  145. Ceramic liquid droplets stabilized in vacuum 査読有り

    R. Takahashi, Y. Tsuruta, Y. Yonezawa, T. Ohsawa, H. Koinuma, Y. Matsumoto

    JOURNAL OF APPLIED PHYSICS 101 (3) 033511 2007年2月

    出版者・発行元:AMER INST PHYSICS

    DOI: 10.1063/1.2433123  

    ISSN:0021-8979

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    We have studied the ceramic liquid droplet of CuOx-added BiOx at high temperature in vacuum. CuOx always floated on the BiOx as a surfactant and suppressed the evaporation of volatile BiOx liquid droplets. A clear liquid behavior of the BiOx droplets was directly observed by in situ laser microscope, with numerous liquid droplets growing by the coalescences in accordance with Marangoni's [Nuovo Cimento Ser. 2, 239 (1872)] effect involved with the precursor film. We have also found a unique absorption of CaO into the BiOx liquid droplets, based on which a reliable process has been established for an atomically flat surface of MgO(001). These results open a broad window of opportunity to tailor not only a chemical interaction on oxide surface but also a liquid droplet dynamics in vacuum. (c) 2007 American Institute of Physics.

  146. Continuous wave infrared laser deposition of organic thin films 査読有り

    Seiichiro Yaginuma, Jun Yamaguchi, Masamitsu Haemori, Kenji Itaka, Yuji Matsumoto, Michio Kondo, Hideomi Koinuma

    COLA'05: 8TH INTERNATIONAL CONFERENCE ON LASER ABLATION 59 520-+ 2007年

    出版者・発行元:IOP PUBLISHING LTD

    DOI: 10.1088/1742-6596/59/1/112  

    ISSN:1742-6588

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    We developed a continuous-wave infrared laser molecular beam epitaxy (CW-IR-LMBE) optimized for the fabrication of organic semiconductor films. The crystal quality of these organic thin films deposited by CW-IR-LMBE was substantially the same as those deposited by thermal evaporation. Due to the possibility of quick switching of evaporation sources, CW-IR-LMBE is especially advantageous for rapid screening of composition, thickness, and fabrication parameters in materials and device optimization based on combinatorial technology.

  147. Flux-mediated epitaxy for ferroelectric Bi4Ti3O12 single crystal film growth 査読有り

    R. Takahashi, Y. Yonezawa, Y. Matsumoto, H. Koinuma

    JOURNAL OF ELECTROCERAMICS 17 (2-4) 189-195 2006年12月

    出版者・発行元:SPRINGER

    DOI: 10.1007/s10832-006-8915-3  

    ISSN:1385-3449

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    We propose the "Flux-mediated epitaxy" as a novel concept for the growth of single crystalline films of incongruent, volatile, and high-temperature-melting compounds. In flux-mediated eptitaxy, by supplying materials precursors from the gas phase through the liquid flux films pre-deposited on the substrate, a quasi-thermodynamic equilibrium condition is obtained at the interface between the growing films and the flux films. This process has been demonstrated in this paper by fabricating ferroelectric Bi4Ti3O12 films, which has volatile Bi oxide. The most important step in this process is the selection of the right flux material, which is hard to predict due to the lack of an appropriate phase diagram. In order to overcome this problem, we have selected the combinatorial approach. A series of ternary flux libraries composed of two self-fluxes (Bi2O3 and Bi4Ti3O12) and a third impurity flux were fabricated on SrTiO3 (001) substrates. After that, stoichiometric Bi4Ti3O12 films were grown on each of these flux libraries at a temperature presumed to melt the flux. High-throughput characterization with the concurrent X-ray diffraction method resulted in the identification of CuO containing Bi2O3 as the flux material for the growth of single crystalline Bi4Ti3O12 films. Stoichiometric Bi4Ti3O12 films fabricated by using a novel CuO containing Bi2O3 are qualified to be single crystalline judging from their large grain size and the electrical properties equivalent to bulk single crystal's.

  148. Field-effect transistor based on atomically flat rutile TiO2 査読有り

    Masao Katayama, Shinya Ikesaka, Jun Kuwano, Yuichi Yamamoto, Hideomi Koinuma, Yuji Matsumoto

    APPLIED PHYSICS LETTERS 89 (24) 242103 2006年12月

    出版者・発行元:AMER INST PHYSICS

    DOI: 10.1063/1.2404980  

    ISSN:0003-6951

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    The authors have fabricated a field-effect transistor (FET) based on a rutile TiO2 active channel. Top-gate transistor structure with an amorphous LaAlO3 insulator was fabricated on the ultrasmoothed rutile single crystals. Reproducible n-type FET actions were observed only by the use of ultrasmoothed TiO2 surfaces. Moreover, an anisotropy of the field-effect mobility depending on the channel direction, which reflects intrinsic nature of rutile, was definitely observed. Inserting MgO insulating buffer between TiO2 and amorphous LaAlO3 suppressed the off-state current and realized on-to-off current ratio as high as 10(4). (c) 2006 American Institute of Physics.

  149. Epitaxial ScAlMgO4(0001) films grown on sapphire substrates by flux-mediated epitaxy 査読有り

    T. Obata, R. Takahashi, I. Ohkubo, M. Oshima, K. Nakajima, T. Chikyow, H. Koinuma, Y. Matsumoto

    APPLIED PHYSICS LETTERS 89 (19) 191910 2006年11月

    出版者・発行元:AMER INST PHYSICS

    DOI: 10.1063/1.2387124  

    ISSN:0003-6951

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    ScAlMgO4(0001) epitaxial films have been synthesized on sapphire (0001) substrates by flux-mediated epitaxy. The key points were high temperature deposition and the use of additive BiOx, which was simultaneously supplied during the deposition; otherwise the growth of spinel phase such as MgAl2O4 was dominant. The BiOx is thus considered to promote the growth of ScAlMgO4 like a flux. This result indicates that the flux-mediated epitaxy is a promising way to high quality single crystal ScAlMgO4 films as a lattice-matched substrate for p-type ZnO and GaN films.

  150. Large magnetic anisotropy in highly c-axis-oriented RuEu1.5Ce0.5Sr2Cu2O10-delta epitaxial films 査読有り

    W. Q. Lu, Y. Yamamoto, K. Itaka, V. V. Petrykin, M. Kakihana, Y. Matsumoto, T. Hasegawa, H. Koinuma

    PHYSICAL REVIEW B 74 (9) 092402 2006年9月

    出版者・発行元:AMERICAN PHYSICAL SOC

    DOI: 10.1103/PhysRevB.74.092402  

    ISSN:1098-0121

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    We investigated the magnetic properties in Ru(Eu1.5Ce0.5)Sr2Cu2O10-delta (Ru-1222) epitaxial films. Large magnetic anisotropy was observed, showing that the c axis is the hard axis of magnetization, while all the directions in the ab plane are isotropic easy axes for magnetization. A possible arrangement of the Ru moments is suggested to interpret the magnetic anisotropy as well as the complex magnetic properties of Ru-1222 including the ferromagnetic, the antiferromagnetic, and the spin-glass behaviors.

  151. High-mobility C-60 field-effect molecular-wetting controlled transistors fabricated on substrates 査読有り

    Kenji Itaka, Mitsugu Yamashiro, Jun Yamaguchi, Masamitsu Haemori, Seiichiro Yaginuma, Yuji Matsumoto, Michio Kondo, Hideomi Koinuma

    ADVANCED MATERIALS 18 (13) 1713-+ 2006年7月

    出版者・発行元:WILEY-V C H VERLAG GMBH

    DOI: 10.1002/adma.200502752  

    ISSN:0935-9648

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    An atomically flat pentacene monomolecular layer remarkably improved the crystallinity of C-60 films, thus enhancing the field-effect mobilities in C-60 transistors (FETs) (see figure). They showed a four to five times better performance over devices with C-60 films grown without a pentacene buffer. Molecular-wetting-controlled substrates can thus offer a general solution to the fabrication of high-performance crystalline organic devices.

  152. Correlation between flux pinning and inhomogeneous electronic distribution of Bi2Sr2CaCu2O8+delta directly probed by scanning tunneling microscopy/spectroscopy 査読有り

    Noritaka Fukuo, Hideki Mashima, Yuji Matsumoto

    PHYSICAL REVIEW B 73 (22) 220505 2006年6月

    出版者・発行元:AMERICAN PHYSICAL SOC

    DOI: 10.1103/PhysRevB.73.220505  

    ISSN:1098-0121

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    The correlation between the vortex distribution and electronic inhomogeneity in Bi2Sr2CaCu2O8+delta single crystals has been studied by scanning tunneling microscopy/spectroscopy at 4.3 K under 8 T. Vortices have been visualized by mapping the differential tunneling conductance at 12.5 meV, at which quasiparticles form a bound state. We found that vortices tend to form a triangular lattice with a spacing of a(0)=1.07(phi(0)/B)(1/2) within a short range of similar to a(0), but that the triangular correlation is absent at longer ranges. By comparing the vortex distribution pattern and the spatial map of the gap value, we conclude that the vortices are predominantly trapped in the regions displaying relatively large gaps and rounded gap edges.

  153. Direct observation of interlayer josephson vortices in heavily Pb-doped Bi2Sr2CaCu2Oy by scanning superconducting quantum interference device microscopy 査読有り

    Junpei Kasai, Noriaki Okazaki, Yuri Nakayama, Teruki Motohashi, Jun-ichi Shimoyama, Kohji Kishio, Yuji Matsumoto, Hideomi Koinuma, Tetsuya Hasegawa

    JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS & EXPRESS LETTERS 45 (17-19) L490-L492 2006年5月

    出版者・発行元:JAPAN SOC APPLIED PHYSICS

    DOI: 10.1143/JJAP.45.L490  

    ISSN:0021-4922

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    Josephson vortices trapped in cross-sectional edge surfaces of Pb0.6Bi1.4Sr2CaCu2Oy has been directly observed by using a scanning superconducting quantum interference device (SQUID) microscope. The magnetic field distribution B-z around each vortex is substantially anisotropic, compared with the usual vortex in the ab-plane, and is extended over 100 mu m toward the in-plane direction. By fitting a theoretical B, function to experimental ones, c-axis penetration depth lambda(c) was estimated to be 11.2 +/- 0.7 mu m, which is in good agreement with the literature value, 12.6 mu m, obtained from the Josephson plasma edge frequency.

  154. Nanoskyscrapers of ferroelectric Bi4Ti3O12 査読有り

    R Takahashi, Y Yonezawa, K Nakajima, T Chikyow, H Koinuma, Y Matsumoto

    APPLIED PHYSICS LETTERS 88 (15) 152904 2006年4月

    出版者・発行元:AMER INST PHYSICS

    DOI: 10.1063/1.2173720  

    ISSN:0003-6951

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    Self-assembled nanoskyscrapers of ferroelectric Bi4Ti3O12 were fabricated by a bottom-up process: flux-mediated epitaxy using an admixture flux. By combinatorial technique, we have discovered a novel flux, VOx, to assist the unique crystal growth for the in-plane alignment of the long c axis of Bi4Ti3O12 on a SrTiO3(001) substrate. We report on the self-assembly of an isolated epitaxial (110)-oriented Bi4Ti3O12 nanoplate and the direct measurement of the piezoelectric properties by a scanning probe microscope technique. Piezoelectric lattice displacement showed a typical butterfly curve, indicating good ferroelectric property.

  155. Photochemical approach to analysis of ferroelectric transition in BaxSr1-xTiO3 epitaxial films 査読有り

    K Ohara, T Ohsawa, H Koinuma, Y Matsumoto

    JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS & EXPRESS LETTERS 45 (8-11) L339-L342 2006年3月

    出版者・発行元:INST PURE APPLIED PHYSICS

    DOI: 10.1143/JJAP.45.L339  

    ISSN:0021-4922

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    When Sr1-xBaxTiO3 (0 &lt; x &lt; 1) epitaxial film is illuminated with UV-visible light (377 to 483 nm) in aqueous AgNO3 Solutions, a photochemical reaction product of Ag is deposited oil the film surface. The compositional dependences of the amount of Ag and band gap show an abrupt change at x = 0.6, i.e., near Ba0.6Sr0.4TiO3, which has its Curie temperature near room temperature. Oil the basis of ail analysis of these behaviors near the ferroelectric transition, it is found that ferroelectric and paraelectric domains coexist ill the composition ratio range of x = 0.5 to 0.7, as confirmed by X-ray diffraction.

  156. Perfect Bi4Ti3O12 single-crystal films via flux-mediated epitaxy 査読有り

    R Takahashi, Y Yonezawa, M Ohtani, M Kawasaki, K Nakajima, T Chikyow, H Koinuma, Y Matsumoto

    ADVANCED FUNCTIONAL MATERIALS 16 (4) 485-491 2006年3月

    出版者・発行元:WILEY-V C H VERLAG GMBH

    DOI: 10.1002/adfm.200500390  

    ISSN:1616-301X

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    Excellent crystallinity of material films and atomic control of their surface/interface, sufficient for the realization of their optimal physical properties, are technological premises for modern functional-device applications. Bi4Ti3O12 and related compounds attract much interest as highly insulating, ferroelectric materials for use in ferroelectric random-access memories. However, it has been difficult thus far for Bi4Ti3O12 films to satisfy such requirements when formed using vapor-phase epitaxy, owing to the high volatility of Bi in a vacuum. Here, we demonstrate that flux-mediated epitaxy is one of the most promising and widely applicable concepts to overcome this inevitable problem. The key point of this process is the appropriate selection of a multi-component flux system. A combinatorial approach has led to the successful discovery of the novel flux composition of Bi-Cu-O for Bi4Ti3O12 single-crystal film growth. The perfect single-crystal nature of the stoichiometric Bi4Ti3O12 film formed has been verified through its giant grain size and electric properties, equivalent to those of bulk single crystals. This demonstration has broad implications, opening up the possibility of preparing stoichiometric single-crystal oxide films via vapor-phase epitaxy, even if volatile constituents are required.

  157. Electronic inhomogeneity of heavily overdopedBi2−xPbxSr2CuOystudied by low-temperature scanning tunneling microscopy/spectroscopy 査読有り

    H. Mashima, N. Fukuo, Y. Matsumoto, G. Kinoda, T. Kondo, H. Ikuta, T. Hitosugi, T. Hasegawa

    Physical Review B 73 (6) 2006年2月13日

    出版者・発行元:American Physical Society (APS)

    DOI: 10.1103/physrevb.73.060502  

    ISSN:1098-0121

    eISSN:1550-235X

  158. Development of UHV-LT MFM operating in magnetic field 査読有り

    Hidetaka Sugaya, Taro Hitosugi, Toshihiro Shimada, Toshihiko Nagamura, Yuji Matsumoto, Tetsuya Hasegawa

    AIP Conference Proceedings 850 1667-1668 2006年

    DOI: 10.1063/1.2355349  

    ISSN:0094-243X 1551-7616

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    We have developed an ultrahigh-vacuum low-temperature magnetic force microscope (UHV-LT MFM) which can operate in magnetic fields. The microscope is based on a non-contact atomic force microscope using a piezoelectric cantilever. Measurements of hard disc media confirmed spatial resolution of ∼50 nm even at low temperatures down to 10 K. The maximum scanning area is as wide as 2.5 μm × 2.5 μm at 10 K and 7.5 μm × 7.5 μm at room temperature. We have also equipped the microscope with an electromagnet in order to apply external magnetic fields up to 0.25 T in the horizontal direction. The MFM head is mounted on a piezo-driven rotation stage, so that the direction of magnetic field relative to the sample surface can be set arbitrarily. © 2006 American Institute of Physics.

  159. Correlation between vortex distribution and electronic inhomogeneity in Bi2Sr2CaCu2O8+delta as probed by STM/STS 査読有り

    Noritaka Fukuo, Hideki Mashima, Go Kinoda, Taro Hitosugi, Toshihiro Shimada, Keisuke Shimizu, Jun-ichi Shimoyama, Kohji Kishio, Yuji Matsumoto, Tetsuya Hasegawa

    LOW TEMPERATURE PHYSICS, PTS A AND B 850 797-+ 2006年

    出版者・発行元:AMER INST PHYSICS

    DOI: 10.1063/1.2354945  

    ISSN:0094-243X

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    In order to investigate the correlation between vortex distribution and inherent electronic inhomogeneity, we have performed scanning tunneling microscopy/spectroscopy (STM/STS) of optimally doped Bi2Sr2CaCu2O8+delta single crystals at 4.3 K under 8 T. Vortices have been successfully visualized by mapping differential tunneling conductance at 12.5 meV, which was substantially enhanced around the vortex cores. The vortices tended to form an ordinary triangular lattice with a spacing of a(0) = 1.07 root phi/B in a short range of similar to a(0), but the triangular correlation was almost missing in a longer scale. By comparing the vortex distribution pattern and gap map, we concluded that pseudogap, regions predominantly pin down vortices.

  160. Scanning tunneling microscopy/spectroscopy of heavily overdoped Bi2Sr2CuOy single crystals 査読有り

    Hideki Mashima, Noritaka Fukuo, Go Kinoda, Taro Hitosugi, Toshihiro Shimada, Takeshi Kondo, Yoshinori Okada, Hiroshi Ikuta, Yuji Matsumoto, Tetsuya Hasegawa

    LOW TEMPERATURE PHYSICS, PTS A AND B 850 509-+ 2006年

    出版者・発行元:AMER INST PHYSICS

    DOI: 10.1063/1.2354808  

    ISSN:0094-243X

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    We have carried out scanning tunneling microscopy/spectroscopy (STM/STS) of heavily overdoped Bi2Sr2CuOy single crystals with T-c &lt; 2 K. STS spectra showed a pseudogap structure with dull coherence peaks. Furthermore, we found that the magnitude of pseudogap is spatially non-uniform in a nm scale and varies from 10 to 30 meV. This supports a scenario that the electronic inhomogeneity is a consequence of randomly distributed Coulomb potential in the CuO2 layers induced by disorder of excess oxygen in the BiO layers.

  161. Design and development of an ultra-compact drum-shaped chamber for combinatorial pulsed laser deposition 査読有り

    M Katayama, K Itaka, Y Matsumoto, H Koinuma

    APPLIED SURFACE SCIENCE 252 (7) 2461-2465 2006年1月

    出版者・発行元:ELSEVIER SCIENCE BV

    DOI: 10.1016/j.apsusc.2005.06.042  

    ISSN:0169-4332

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    We have designed a compact combinatorial pulsed laser deposition (PLD) chamber as a building block of a desktop laboratory for advanced materials research. Development of small-size systems for the growth and characterization of films would greatly help in interconnecting a variety of analytical tools for rapid screening of advanced materials. This PLD chamber has four special features: (1) a drum-shaped growth chamber, (2) a waterwheel-like combinatorial masking system, (3) a multi-target system having one feedthrough, and (4) a small reflection high-energy electron diffraction (RHEED) system. The performance of this system is demonstrated by the RHEED intensity oscillation during homoepitaxial growth of SrTiO3 as well as by simultaneous fabrication of a ternary phase diagram of rare earth-doped Y2O3 phosphors. (c) 2005 Elsevier B.V. All rights reserved.

  162. Combinatorial exploration of flux material for Bi4Ti3O12 single crystal film growth 査読有り

    R Takahashi, Y Yonezawa, M Ohtani, M Kawasaki, Y Matsumoto, H Koinuma

    APPLIED SURFACE SCIENCE 252 (7) 2477-2481 2006年1月

    出版者・発行元:ELSEVIER SCIENCE BV

    DOI: 10.1016/j.apsusc.2005.05.092  

    ISSN:0169-4332

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    The combinatorial approach to materials synthesis was employed for the quick screening of a flux material for liquid phase-mediated epitaxy of Bi4Ti3O12 single crystal film. A series of ternary flux libraries composed of two self-fluxes (Bi2O3 and Bi4Ti3O12) and an impurity flux (VOx, WOx, CuOx, BiPOx, BaO, MoOx) were fabricated on the SrTiO3 (0 0 1) substrates. Then, stoichiometric Bi4Ti3O12 was grown on each one of these flux libraries at a temperature presumed to melt the flux. High-throughput characterization with the concurrent X-ray diffraction (XRD) method resulted in the discovery of a novel flux material, CuO, containing Bi2O3, for Bi4Ti3O12 single crystal film. (c) 2005 Elsevier B.V. All rights reserved.

  163. A combinatorial approach to the discovery and optimization of YCa4O(BO3)(3)-based luminescent materials 査読有り

    H Sano, T Matsumoto, Y Matsumoto, H Koinuma

    APPLIED SURFACE SCIENCE 252 (7) 2493-2496 2006年1月

    出版者・発行元:ELSEVIER SCIENCE BV

    DOI: 10.1016/j.apsusc.2005.05.091  

    ISSN:0169-4332

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    Thin films of YCa4O(BO3)(3) (YCOB)-based new luminescent materials were explored by the combinatorial pulsed laser deposition (PLD) method which enabled us to fabricate continuous composition spread film libraries. Strong red and green luminescence were found in the Y1-xEuxCOB (0 &lt;= x &lt;= 1), (YEuCOB) and Y1-yTbyCOB (0 &lt;= y &lt;= 1) (YThCOB) films, respectively. The film libraries were characterized by photoluminescence (PL), PL decay, an electron-probe microanalyzer and an electron diffraction analysis. The luminescent intensities in the amorphous film libraries strongly depended on the chemical composition of each rare-earth (RE) ion. The optimum concentration of rare-earth ions in YEuCOB and YTbCOB were experimentally determined to be Eu = 7.5% and Tb = 20-30%, respectively. (c) 2005 Elsevier B.V. All rights reserved.

  164. Combinatorial synthesis of Li-doped NiO thin films and their transparent conducting properties 査読有り

    US Joshi, Y Matsumoto, K Itaka, M Sumiya, H Koinuma

    APPLIED SURFACE SCIENCE 252 (7) 2524-2528 2006年1月

    出版者・発行元:ELSEVIER SCIENCE BV

    DOI: 10.1016/j.apsusc.2005.03.239  

    ISSN:0169-4332

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    Transparent and conductive oxide (TCO) thin films of Li-doped NiO were prepared by combinatorial pulsed laser deposition technique. Composition spread approach was applied to optimize the Li concentration for achieving high conductivity and transparency in the film. Conductivity of the composition spread film was found to increase almost linearly from nearly insulating to as high as 1.41 Omega(-1) cm(-1) with increasing Li content along a 9 mm long film. Optical transparency was found to decrease in an equal proportion across the 40 nm thick film with a slight shift in the absorption edge. (c) 2005 Published by Elsevier B.V.

  165. Combinatorial discovery of anomalous substrate effect on the photochemical properties of transition metal-doped epitaxial SrTiO3 heterostructures 査読有り

    T Ohsawa, K Nakajima, Y Matsumoto, H Koinuma

    APPLIED SURFACE SCIENCE 252 (7) 2603-2607 2006年1月

    出版者・発行元:ELSEVIER SCIENCE BV

    DOI: 10.1016/j.apsusc.2005.05  

    ISSN:0169-4332

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    Epitaxial Sr(VxCryTi1-x-y) O-3 (0 &lt;= x + y &lt;= 0.05) ternary cornposition spreads were grown on two different single crystal substrates, LaAlO3 and Nb-doped SrTiO3, by use of combinatorial laser molecular beam epitaxy with a specially patterned slide masking plate. The photocatalytic activity on the composition spreads was evaluated by the photo-reduction of Ag+ in an AGNO(3) aqueous solution to deposit Ag metal on the spreads. The V-doping effect was found to depend greatly on the substrate: the photodeposition of Ag was much enhanced in the composition region of SrV0.05Ti0.95O3 only on the Nb-doped SrTiO3, but not on the LaAlO3 and non-doped SrTiO3. (c) 2005 Elsevier B.V. All rights reserved.

  166. High-throughput characterization of local conductivity of Nd0.9Ca0.1. Ba2CU3O7-delta thin film by the low-temperature scanning microwave microscope 査読有り

    S Okazaki, N Okazaki, XR Zhao, H Sugaya, S Yaginuma, R Takahashi, M Murakami, Y Matsumoto, T Chikyow, H Koinuma, T Hasegawa

    APPLIED SURFACE SCIENCE 252 (7) 2615-2621 2006年1月

    出版者・発行元:ELSEVIER SCIENCE BV

    DOI: 10.1016/j.apsusc.2005.05.077  

    ISSN:0169-4332

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    We developed a scanning microwave microscope (S mu M) designed for high-throughput electric-property screening as well as for rapid construction of electronic phase diagrams at low temperatures. As a sensor probe, we used a high-Q lambda/4 coaxial cavity resonator to which a thin needle with ball-tip end was attached. The sensor module was Mounted on the low-temperature XYZ stage, which allowed us to map out the change of resonance frequency and quality factor due to the local tip-sample interaction at low temperatures. From the measurements of combinatorial thin films, such as Ti1-xCoxO2-delta and Nd0.9Ca0.1Ba2Cu3O7-delta (NCBCO), it was demonstrated that this S mu M system has enough performance for the high-throughput characterization of sample conductance under variable temperature conditions. (c) 2005 Elsevier B.V. All rights reserved.

  167. High-throughput characterization of BixY3-xFe5O12 combinatorial thin films by magneto-optical imaging technique 査読有り

    XR Zhao, WQ Lu, S Okazaki, Y Konishi, K Akahane, T Ishibashi, K Sato, Y Matsumoto, H Koinuma, T Hasegawa

    APPLIED SURFACE SCIENCE 252 (7) 2628-2633 2006年1月

    出版者・発行元:ELSEVIER SCIENCE BV

    DOI: 10.1016/j.apsusc.2005.05.090  

    ISSN:0169-4332

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    BixY3-xFe5O12 thin films have been grown on GGG (Gd3Ga5O12) (1 1 1) substrates by the combinatorial composition-spread techniques under substrate temperature (T-sub) ranging from 410 to 700 degrees C and O-2 pressure of 200 mTorr. In order to study the effect of substrates on the deposition of BixY3-xFe5O12 thin films, gamet substrates annealed at 1300 degrees C for 3 h were also used. Magneto-optical properties were characterized by our home-designed magneto-optical imaging system. From the maps of Faraday rotation angle theta(F), it was evident that the Faraday effect appears only when T-sub = 430-630 degrees C. theta(F) reaches to the maximum value (similar to 6 degrees/mu m, lambda = 632 nm) at 500 degrees C, and is proportional to the Bi contents. XRD and EPMA analyses showed that Bi ions are easier to substitute for Y sites and better crystallinity is obtained for annealed substrates than for commercial ones. (c) 2005 Elsevier B.V. All rights reserved.

  168. RECa4O(BO3)(3) thin films as new Luminescent materials screened by the combinatorial method 査読有り

    H Sano, T Matsumoto, Y Matsumoto, H Koinuma

    JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS 66 (11) 2112-2115 2005年11月

    出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD

    DOI: 10.1016/j.jpcs.2005.09.081  

    ISSN:0022-3697

    詳細を見る 詳細を閉じる

    A new phosphor material, Y1-xTbxCa4O(BO3)(3) (0 &lt;= x &lt;= 1) film was grown on SiO2 substrates by the combinatorial pulsed laser deposition (PLD) method, which enabled us to fabricate continuous composition spread film libraries. Photoluminescence (PL) and PL decay were measured for these film libraries to identify the optimum composition as well as to determine the luminescence mechanism. The film libraries showed strong dependence of luminescence intensities on the chemical composition of Tb ion. The optimum concentration of Tb ions in Y1-xTbxCa4O(BO3)(3) was experimentally and theoretically determined to be x = 0.2-0.3. (c) 2005 Elsevier Ltd. All rights reserved.

  169. Surface termination effect on the photocatalysis on atomically controlled SrTiO3(001) surface 査読有り

    Y Matsumoto, T Ohsawa, R Takahashi, H Koinuma

    THIN SOLID FILMS 486 (1-2) 11-14 2005年8月

    出版者・発行元:ELSEVIER SCIENCE SA

    DOI: 10.1016/j.tsf.2004.10.054  

    ISSN:0040-6090

    詳細を見る 詳細を閉じる

    We have demonstrated a surface termination effect on the photo decomposition of a monolayer (ML) pentacene film on the SrTiO3(001) single crystal surface. To prepare SrO-terminated SrTiO3(001), a SrO thin film was deposited on TiO2-terminated SrTiO3(001) by a laser molecular beam epitaxy method. The coverage of the SrO layer was precisely controlled utilizing in-situ reflection high energy electron diffraction (RHEED) intensity monitoring. The photodecomposition of the pentacene film was directly observed and quantitatively analyzed by an atomic force microscope (AFM). The 1 ML SrO was enough to completely suppress the photodecomposition of the pentacene film on SrTiO3(001). The electron transfer process from the bulk to electron scavengers such as adsorbed O-2 molecules at the surface depended greatly on the choice of the surface termination layer of SrTiO3(001), (c) 2004 Elsevier BY All rights reserved.

  170. c-axis oriented epitaxial Ru(Eu1.5Ce0.5)Sr2Cu2O10-delta thin films grown by flux-mediated solid phase epitaxy 査読有り

    WQ Lu, Y Yamamoto, VV Petrykin, M Kakihana, Y Matsumoto, US Joshi, H Koinuma, T Hasegawa

    THIN SOLID FILMS 486 (1-2) 79-81 2005年8月

    出版者・発行元:ELSEVIER SCIENCE SA

    DOI: 10.1016/j.tsf.2004.11.216  

    ISSN:0040-6090

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    Epitaxial thin films of RuSr2(Eu1.5Ce0.5)Cu-1.5(Ru-1222), which attracts much attention as a magnetic superconductor, were grown on SrTiO3 (001) substrate by a "flux-mediated reactive solid phase epitaxy" technique. The films were highly c-oriented and contained no randomly aligned phases. The superconducting transition was observed at 25 K coexisting with the weak ferroniagnetic order. Magnetic anisotropy was observed between the in-plane and out-of-plane directions. (c) 2005 Elsevier B.V All rights reserved.

  171. Structure of NiO and Li-doped NiO single crystalline thin layers with atomically flat surface 査読有り

    US Joshi, R Takahashi, Y Matsumoto, H Koinuma

    THIN SOLID FILMS 486 (1-2) 214-217 2005年8月

    出版者・発行元:ELSEVIER SCIENCE SA

    DOI: 10.1016/j.tsf.2004.11.219  

    ISSN:0040-6090

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    Crystalline thin films of NiO and nominally 20 at.% Li-doped NiO were deposited at room temperature by pulsed laser deposition on the lattice matched MgO (100) substrate. As-deposited films were annealed at various temperatures to promote a solid phase epitaxial growth and control the surface morphology. Films were characterized by AFM and RHEED measurements. AFM images of the NiO film annealed at 1200 degrees C for 30 min showed an atomically flat surface and an excellent step-terrace morphology with a step height corresponding to one unit cell of NiO over a wide range of 2 mu m X 2 mu m. Formation of atomically smooth surface in a range of annealing temperatures is highlighted and a temperature of 1200 degrees C is identified as being the most suitable in the solid phase epitaxy for single crystalline growth and a smooth surface of the films deposited by PLD. (c) 2005 Elsevier B.V. All rights reserved.

  172. Sharp metal-insulator transition in Sr(Ti1-xVx)O3-delta thin films on SrTiO3 substrates 査読有り

    K Itaka, T Wakisaka, Mihara, I, S Yaginuma, Y Matsumoto, H Koinuma

    THIN SOLID FILMS 486 (1-2) 222-225 2005年8月

    出版者・発行元:ELSEVIER SCIENCE SA

    DOI: 10.1016/j.tsf.2004.11.230  

    ISSN:0040-6090

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    We fabricated Sr(Ti1-xVx)O-3 composition-spread films on SrTiO3 (100) substrates by using pulsed laser deposition in ultra high vacuum. Sharp metal-insulator (M 1) transitions were observed in the case of Sr(Ti1-xVx)O3-delta composition-spread films grown on an oxygen deficient SrTiO3 (STO) buffer/SrTiO3 (STO) substrate in the restricted composition x=0.5-1.0 while no MI transition was observed in the case of Sr(Ti1-xVx)O3-delta belowx=0.5. In the insulating phase below the MI transition, non-linear I-V characteristics were observed. To explain the appearance and disappearance of MI transitions in Sr(Ti1-xVx)O3-delta two possibilities were considered: (i) strain effect from the substrate and (ii) charge-transfer at the interface between Sr(Ti1-xVx)O3-delta and STO. (c) 2005 Elsevier B.V. All rights reserved.

  173. Photochemical identification of a possible adsorbed pentacene molecule on the SrTiO3(001) 査読有り

    T Ohsawa, Y Matsumoto, H Koinuma

    JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS 44 (6A) 4142-4144 2005年6月

    出版者・発行元:JAPAN SOC APPLIED PHYSICS

    DOI: 10.1143/JJAP.44.4142  

    ISSN:0021-4922

    詳細を見る 詳細を閉じる

    Photocatalytic decomposition: of the pentacene ultrathin film grown on the TiO2-terminated SrTiO3(001) single crystal substrate is studied. There are two kinds of pentacene on the SrTiO3: One is forming the crystal island as observed by atomic force microscope (AFM), the other is the precursor state adsorbed on the substrate. The latter is photochemically more reactive than the former. The pentacene molecule is released from the crystal island even at a low temperature such as 373 K due to its chemical nature of the van der Waals molecule.

  174. Flux-assisted reactive solid phase epitaxy of highly c-axis oriented Ru(Eu1.5Ce0.5)Sr2Cu2O10-delta thin films 査読有り

    WQ Lu, Y Yamamoto, VV Petrykin, M Kakihana, H Koinuma, K Shibuya, M Lippmaa, Y Matsumoto

    PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS 422 (1-2) 46-50 2005年5月

    出版者・発行元:ELSEVIER SCIENCE BV

    DOI: 10.1016/j.physc.2005.03.006  

    ISSN:0921-4534

    eISSN:1873-2143

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    Highly c-axis oriented epitaxial Ru(Eu1.5Ce0.5)Sr2Cu2O10-delta (Ru-1222) thin films were grown on SrTiO3 (001) substrates by a novel growth technique, flux-assisted reactive solid phase epitaxy. The films grew epitaxially as (100)Ru1222//(100)SrTiO3 with excellent crystallinity and atomically flat terraces and steps. The magnetization data are consistent with that reported for bulk Ru-1222 samples. The films are suggested to be granular superconducting. Although zero resistance was not obtained at temperatures down to 5 K, the onset of superconducting transition was observed at about 25 K within the ferromagnetic order. (c) 2005 Elsevier B.V. All rights reserved.

  175. Crystal-face dependences of surface band edges and hole reactivity, revealed by preparation of essentially atomically smooth and stable (110) and (100) n-TiO2 (rutile) surfaces 査読有り

    R Nakamura, N Ohashi, A Imanishi, T Osawa, Y Matsumoto, H Koinuma, Y Nakato

    JOURNAL OF PHYSICAL CHEMISTRY B 109 (5) 1648-1651 2005年2月

    出版者・発行元:AMER CHEMICAL SOC

    DOI: 10.1021/jp044710t  

    ISSN:1520-6106

    詳細を見る 詳細を閉じる

    Essentially atomically smooth (100) and (110) n-TiO2 (rutile) surfaces were prepared by immersion of commercially available single-crystal wafers in 20% HF, followed by annealing at 600 degreesC in air. The obtained surfaces were stable in aqueous solutions of pH 1-13, showing no change in the surface morphology on an atomic level, contrary to atomically flat surfaces prepared by ion sputtering and annealing under UHV. The success in preparation of the atomically smooth and stable n-TiO2 surfaces enabled us to reveal clear crystal-face dependences of the surface band edges and hole reactivity in aqueous solutions.

  176. Flux-mediated epitaxy: general application in vapor phase epitaxy to single crystal quality of complex oxide films 査読有り

    Y Matsumoto, R Takahashi, H Koinuma

    JOURNAL OF CRYSTAL GROWTH 275 (1-2) 325-330 2005年2月

    出版者・発行元:ELSEVIER SCIENCE BV

    DOI: 10.1016/j.jcrysgro.2004.10.091  

    ISSN:0022-0248

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    We propose a general term flux-mediated epitaxy (FME) to single crystal quality of complex oxide thin films in vapor-phase epitaxy. The key is a flux, which is frequently used in a bulk process for lowering a process temperature and suppressing incongruent melt. The successful application of the flux to the bulk single crystal growth allows us to expect a similar benefit even in the case of vapor-phase epitaxy. In this paper, we discuss on the capability of this general concept &apos;FME&apos; for controlling phases and crystallinity of the complex oxide films, showing some examples such as optical, ferromagnetic oxide and high-T(c) superconductor. (c) 2004 Elsevier B.V. All rights reserved.

  177. Practical translation pattern acquisition from combined language resources 査読有り

    M Kitamura, Y Matsumoto

    NATURAL LANGUAGE PROCESSING - IJCNLP 2004 3248 244-253 2005年

    出版者・発行元:SPRINGER-VERLAG BERLIN

    ISSN:0302-9743

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    Automatic extraction of translation patterns from parallel corpora is an efficient way to automatically develop translation dictionaries, and therefore various approaches have been proposed. This paper presents a practical translation pattern extraction method that greedily extracts translation patterns based on co-occurrence of English and Japanese word sequences, which can also be effectively combined with manual confirmation and linguistic resources, such as chunking information and translation dictionaries. Use of these extra linguistic resources enables it to acquire results of higher precision and broader coverage regardless of the amount of documents.

  178. Fluorescence EXAFS study on local structures around Mn and Fe atoms doped in ZnO 査読有り

    H. Ofuchi, Z. W. Jin, T. Fukumura, M. Kawasaki, Y. Matsumoto, T. Hasegawa, H. Fujioka, M. Oshima, H. Koinuma

    PHYSICA SCRIPTA T115 614-615 2005年

    出版者・発行元:IOP PUBLISHING LTD

    DOI: 10.1238/Physica.Topical.115a00614  

    ISSN:0031-8949

    eISSN:1402-4896

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    In this work, geometric structures for TM-doped (TM = Mn and Fe) ZnO film grown by combinatorial laser molecular beam epitaxy (CLMBE) were investigated using fluorescence EXAFS measurement. The EXAFS analysis has revealed that the majority of TM ions heavily doped in ZnO ([Mn] similar to 20% and [Fe] similar to 1%) substituted the Zn atoms in ZnO lattice.

  179. Preparation of atomically smooth TiO2 single crystal surfaces and their photochemical property 査読有り

    Y Yamamoto, K Nakajima, T Ohsawa, Y Matsumoto, H Koinuma

    JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS & EXPRESS LETTERS 44 (16-19) L511-L514 2005年

    出版者・発行元:INST PURE APPLIED PHYSICS

    DOI: 10.1143/jjap.44.L511  

    ISSN:0021-4922

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    Atomically smooth rutile TiO2(110) (100) (001), (111) and (101) surfaces were obtained for the first time by an appropriate cleaning and subsequent thermal treatment of commercially available single crystals. The annealing temperature for obtaining the ultra-smooth surface varied between 400 and 900 degrees C depending on the crystallographic planes. The key point to the Successful preparation of the regularly stepped TiO2 surface was an HF treatment for the removal of surface impurities. By using these well-defined TiO2 surfaces, the photochemical property was found to depend on the surface orientation; the photoreduction of Ag+ to Ag metal from an aqueous solution proceeded in the order of (10 1) &gt; (100) &gt; (001) &gt; (111) &gt; (110) on the TiO2 surfaces.

  180. Atomic force microscope analysis of photodecomposition of pentacene film on the epitaxial thin film photocatalyst library 査読有り

    Y Matsumoto, T Ohsawa, K Nakajima, H Koinuma

    MEASUREMENT SCIENCE AND TECHNOLOGY 16 (1) 199-202 2005年1月

    出版者・発行元:IOP PUBLISHING LTD

    DOI: 10.1088/0957-0233/16/1/026  

    ISSN:0957-0233

    eISSN:1361-6501

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    We have demonstrated high-throughput synthesis and screening of a thin film photocatalyst library. Pulsed laser deposition enables us to grow the thin film photocatalyst epitaxially with atomically flat terraces and steps. A binary composition spread of [(SrTiO3)(1-x)(LaAlO3)(x)] (0 &lt; x &lt; 1) was fabricated by a combinatorial composition gradient technique. To evaluate the photocatalytic activity for the composition spread, the photodecomposition of pentacene film on the spread was employed and was analysed quantitatively after UV illumination by using an atomic force microscope. For comparison, the photodeposition of Ag from aqueous silver nitrate solution (0.01 M) was also tested. The results obtained from the two methods were basically the same: the SrTiO3-rich region in the film showed greater photocatalytic activity.

  181. Computer design of combinatorial shadow mask for ternary composition spread library 査読有り

    R Takahashi, Y Matsumoto, H Koinuma

    MEASUREMENT SCIENCE AND TECHNOLOGY 16 (1) 292-295 2005年1月

    出版者・発行元:IOP PUBLISHING LTD

    DOI: 10.1088/0957-0233/16/1/038  

    ISSN:0957-0233

    eISSN:1361-6501

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    A simple rotational shadow masking system has been designed by computer simulation for application to the fabrication of a ternary composition spread material library. A mask plate is stencilled off a right triangle pattern and a trapezoid pattern. This can define the thickness gradient of films deposited from three different sources along the axes between the tops and the mid-points of bottom lines of a triangle on a substrate surface. Optimizing the angles of the triangle and trapezoid patterns and regulating the rates of mask moving, the computer simulation predicts that the film thickness of each component varies linearly from one mono-layer at the top to zero at the bottom. This process enables the construction of a ternary phase diagram by repeating the film deposition sequence. This prediction has been mathematically derived in this study.

  182. Y1-xEuxCa4O(BO3)(3) thin film as a luminescent material screened by the combinatorial method 査読有り

    H Sano, T Matsumoto, Y Matsumoto, H Koinuma

    APPLIED PHYSICS LETTERS 86 (2) 021104 2005年1月

    出版者・発行元:AMER INST PHYSICS

    DOI: 10.1063/1.1844044  

    ISSN:0003-6951

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    A phosphor material, Y1-xEuxCa4O(BO3)(3) (0less than or equal toxless than or equal to1) film, was fabricated on SiO2 substrates by the combinatorial laser molecular-beam epitaxy method. Photoluminescence (PL) and PL decay were measured for this film library to identify the optimum composition as well as to determine the luminescence mechanism. Results showed that the observed intense emission peak at 615 nm originated from the electric dipole D-5(0)--&gt;F-7(2) transition of Eu3+. This strong emission makes this red phosphor particularly applicable in devices such as plasma display panels and Xe lamps. (C) 2005 American Institute of Physics.

  183. Homo-epitaxial growth of rutile TiO2 film on step and terrace structured substrate 査読有り

    Y Yamamoto, Y Matsumoto, H Koinuma

    APPLIED SURFACE SCIENCE 238 (1-4) 189-192 2004年11月

    出版者・発行元:ELSEVIER SCIENCE BV

    DOI: 10.1016/j.apsusc.2004.05.206  

    ISSN:0169-4332

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    The atomically finished rutile TiO2 (001) substrate was obtained by an appropriate surface cleaning and subsequent annealing of commercially available single crystals. The morphology, composition and crystallinity of the ultrasmooth surface were confirmed by an atomic force microscope (AFM), an X-ray photoelectron spectroscopy (XPS) and a reflection-high-energy-electron diffraction (RHEED), respectively. The optimum process for obtaining the ultrasmooth surface was found to be the annealing at the temperature of 700 degreesC for 1 h in air after the ultrasonic cleaning immersing in organic solvents and subsequent 20% HF water solution. Furthermore, the homo-epitaxial growth on the ultrasmooth substrate was performed and compared with the hetero-epitaxial growth of TiO2 film on a stepped alpha-Al2O3 (1012) substrate. (C) 2004 Elsevier B.V. All rights reserved.

  184. Electric field effect in pulsed laser deposition of epitaxial ZnO thin film 査読有り

    C Hirose, Y Matsumoto, Y Yamamoto, H Koinuma

    APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING 79 (4-6) 807-809 2004年9月

    出版者・発行元:SPRINGER

    DOI: 10.1007/s00339-004-2568-3  

    ISSN:0947-8396

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    We have developed a new system in which thin films can be pulsed laser deposited under an external electric field. Application of 1 kV high voltage to a thin metal wire placed 1 mm above an edge of a 14 mm long substrate distributes electric fields ranging from 4500 V/cm at the left to 50 V/cm at the right side of the substrate. The crystallinity of the ZnO thin film was remarkably improved in the area where the electric field higher than +100 V/cm was applied during the film deposition. Thus, the film growth of ZnO with a strong polarity along the c-axis was verified to depend on an external electric field.

  185. Cobalt valence states and origins of ferromagnetism in Co doped TiO2 rutile thin films 査読有り

    M Murakami, Y Matsumoto, T Hasegawa, P Ahmet, K Nakajima, T Chikyow, H Ofuchi, Nakai, I, H Koinuma

    JOURNAL OF APPLIED PHYSICS 95 (10) 5330-5333 2004年5月

    出版者・発行元:AMER INST PHYSICS

    DOI: 10.1063/1.1695598  

    ISSN:0021-8979

    eISSN:1089-7550

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    Co doped rutile thin films were fabricated on alpha-Al2O3 (10-12) substrates by laser molecular beam epitaxy. X-ray diffraction, scanning electron microscopy, and transmission electron microscopy indicated that the rutile thin films are (101) oriented and have smooth surfaces with no impurity phases. Co K-edge x-ray absorption near-edge structure, extended x-ray absorption fine structure, and x-ray photoelectron spectroscopy revealed the coexistence of different valence states of Co in the film. Magnetic circular dichroism studies suggest that the observed ferromagnetism is uniform and is related to the electron band structure of TiO2 rutile. Contribution of oxidized (Co2+) and metallic (Co-0) cobalt to the ferromagnetism is discussed. (C) 2004 American Institute of Physics.

  186. Epitaxial Thin Film Growth of Magnetic Super conductor (Eu<SUB>1.5</SUB>Ce<SUB>0.5</SUB>)RuSr<SUB>2</SUB>Cu<SUB>2</SUB>O<SUB>10-δ</SUB> 査読有り

    W.Q.Lu, Y.Yamamoto, I.Ohkubo, V.V.Petrykin, M.Kakihana, Y.Matsumoto, H.Hasegawa, H.Koinuma

    Transactions of the Materials Research Society of Japan (29) 1285-1288 2004年4月

  187. X-ray magnetic circular dichroism and structural model for co-doped Tio(2) (Anatase) thin film 査読有り

    N Shimizu, S Sasaki, T Hanashima, K Yamawaki, H Udagawa, N Kawamura, M Suzuki, H Maruyama, M Murakami, Y Matsumoto, H Koinuma

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN 73 (4) 800-803 2004年4月

    出版者・発行元:PHYSICAL SOC JAPAN

    DOI: 10.1143/JPSJ.73.800  

    ISSN:0031-9015

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    We have succeeded in measuring fluorescence X-ray magnetic circular dichroism (XMCD) and absorption spectra at the Co K absorption edge for a small amount of doped Co ions in a CoxTi1-xO2 anatase film (x = 0.07; 700-Angstrom-thickness) on a LaAlO3 (001) substrate. X-ray fluorescence intensity was accumulated for 3d at the pseudo-total-reflection geometry in a synchrotron undulator beamline, BL39XU at SPring-8. Negative-to-positive dispersion-type XMCD spectra were clearly observed at E = 7.725 keV, suggesting the ferromagnetism at room temperature and unlikelihood on the existence of Co-metal clusters. XANES spectra support the Co2+ oxidation state and participation of a partial structure of ilmenite-type CoTiO3. We have proposed a crystal structure of Co-doped anatase films and the ferromagnetic order scheme by Co-Ti-O polysynthetic twin lamellae. A (012) CoTiO3 layer interstitially distributes parallel to the (001) plane of anatase and replaces a quarter of the anatase cell at intervals of three and half times of the cell along the c axis.

  188. Combinatorial scanning tunneling microscopy study of Cr deposited on anatase TiO2(001) surface 査読有り

    T Ohsawa, Y Yamamoto, M Sumiya, Y Matsumoto, H Koinuma

    LANGMUIR 20 (8) 3018-3020 2004年4月

    出版者・発行元:AMER CHEMICAL SOC

    DOI: 10.1021/la034794h  

    ISSN:0743-7463

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    We have investigated Cr deposited on anatase TiO2(001) surfaces using a combinatorial approach. Anatase TiO2(001) thin films covered with Cr metals were prepared on a Nb-doped SrTiO3(001) substrate by combinatorial laser molecular beam epitaxy and characterized by in situ low-energy electron diffraction and ultrahigh vacuum (UHV) scanning tunneling microscopy (STM). STM images of a clean TiO2(001) surface showed that one-dimensional structures along the [100] and [010] directions were formed, resulting in a (1 x 4) surface reconstruction. When Cr atoms were deposited on the anatase TiO2 surface and the films were annealed at 900 K in UHV, the one-dimensional structures became branched and showed short-range disorder. The observed surface structural disordering will be discussed in terms of the lattice strain induced by the Cr atoms diffused into the bulk.

  189. Highly c-oriented RuSr2(Eu1.5Ce0.5)Cu2O10-delta thin film growth by pulsed laser deposition and subsequent post-annealing 査読有り

    WQ Lu, Y Yamamoto, Ohkubo, I, VV Petrykin, M Kakihana, Y Matsumoto, H Koinuma

    PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS 403 (1-2) 21-24 2004年3月

    出版者・発行元:ELSEVIER SCIENCE BV

    DOI: 10.1016/j.physc.2003.11.003  

    ISSN:0921-4534

    eISSN:1873-2143

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    A RuSr2(Eu1.5Ce0.5)Cu2O10-delta (Ru-1222) sintered target was laser ablated into thin films on SrTiO3 (001) substrates at temperatures between room temperature and 800 degreesC. Although the as-deposited films did not exhibit Ru-1222 phase, the films deposited at temperatures between 600 and 780 degreesC were successfully crystallized and exhibited highly c-axis oriented Ru-1222 phase by the subsequent thermal treatment under appropriate conditions. The films grown at 740 degreesC and annealed at 1060 degreesC in 1 atm oxygen flow for 1 h showed a weak ferromagnetic behavior below 130 K and the onset of superconducting transition at 32.4 K. The coexistence of ferromagnetism and superconductivity was observed at temperatures below 32.4 K. (C) 2003 Elsevier B.V. All rights reserved.

  190. Fabrication of Nd1-xCaxBa2Cu3O7-delta (x=0-0.3) single crystalline films by tri-phase epitaxy 査読有り

    Takahashi, R Matsumoto, Y Kohno, T Kawasaki, M Koinuma, H

    J. Cryst. Growth 262 (1-4) 308-312 2004年2月15日

    DOI: 10.1016/j.jcrysgro.2003.07.036  

  191. A new catalyst for selective oxidation of CO in H-2: Part 1, activation by depositing a large amount of FeOx on Pt/Al2O3 and Pt/CeO2 catalysts 査読有り

    K Tanaka, Y Moro-oka, K Ishigure, T Yajima, Y Okabe, Y Kato, H Hamano, S Sekiya, H Tanaka, Y Matsumoto, H Koinuma, H He, CB Zhang, QC Feng

    CATALYSIS LETTERS 92 (3-4) 115-121 2004年2月

    出版者・発行元:KLUWER ACADEMIC/PLENUM PUBL

    DOI: 10.1023/B:CATL.0000014333.84509.1a  

    ISSN:1011-372X

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    1% Pt/Al2O3 and 1% Pt/CeO2 are markedly activated by the deposition of a large quantity of FeOx, about 100 wt% in Fe with respect to the supports. In contrast, the activity of a Ru/Al2O3 catalyst was completely suppressed by the deposition of FeOx, but a Ru-Pt/Al2O3 was markedly activated by the FeOx. The activation depends on the sequence of the deposition, that is, no pronounced activation was observed on the Pt supported on a FeOx/Al2O3 as well as on the Pt codeposited with a small amount of Fe on Al2O3, that is, the activity was almost equal to that of the Pt/Al2O3. The XPS analysis of the Pt/CeO2 and FeOx/Pt/CeO2 proved that the Pt is effectively covered with the FeOx. Selectivity for the oxidation of CO in H-2 was also improved on the FeOx/Pt/Al2O3 and FeOx/Pt/CeO2 catalysts and it is rather independent of the conversion. In conformity with the feature of the FeOx/Pt/Al2O3 and FeOx/Pt/CeO2 catalysts, we deduced that the deposited FeOx is activated by the Pt and the FeOx is responsible for the selective oxidation of CO.

  192. Mathematical design of linear action masks for binary and ternary composition spread film library 査読有り

    Y Yamamoto, R Takahashi, Y Matsumoto, T Chikyow, H Koinuma

    APPLIED SURFACE SCIENCE 223 (1-3) 9-13 2004年2月

    出版者・発行元:ELSEVIER SCIENCE BV

    DOI: 10.1016/j.apsusc.2003.10.025  

    ISSN:0169-4332

    eISSN:1873-5584

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    Composition spread is a powerful method to search for new functional materials. In this paper, we list and discuss various continuous composition spread techniques, and propose a new combinatorial masking system for concurrent fabrication of binary and of ternary phase diagrams in which compositions of each component cover the full range of 0-100%. (C) 2003 Elsevier B.V. All rights reserved.

  193. Combinatorial investigation of transition metals deposited on anatase TiO2 surface 査読有り

    T Ohsawa, Y Matsumoto, H Koinuma

    APPLIED SURFACE SCIENCE 223 (1-3) 84-86 2004年2月

    出版者・発行元:ELSEVIER SCIENCE BV

    DOI: 10.1016/j.apsusc.2003.10.021  

    ISSN:0169-4332

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    By using a combinatorial laser molecular beam epitaxy (MBE)/in situ low energy electron diffraction (LEED) and scanning tunneling microscope (STM) system, we have investigated a behavior of transition metals (TMs) deposited on the anatase TiO2 (0 0 1)-(4 x 1) surface systematically. TiO2 (0 0 1) thin films were fabricated on 0.05 mol% Nb doped SrTiO3 (0 0 1) substrates and on each of those films TMs were deposited with gradual variation of its deposition amount. In situ analysis of the libraries with LEED and STM revealed the surface morphologies that were sensitive to TM element and on the process temperature. The results are discussed in terms of the oxide formation enthalpy DeltaH kJ mol(-1) of TMs. (C) 2003 Elsevier B.V. All rights reserved.

  194. Characterization of LiNb1-xTaxO3 composition-spread thin film by the scanning microwave microscope 査読有り

    N Okazaki, S Okazaki, H Higuma, S Miyashita, Y Cho, J Nishimura, T Fukumura, M Kawasaki, M Murakami, Y Yamamoto, Y Matsumoto, H Koinuma, T Hasegawa

    APPLIED SURFACE SCIENCE 223 (1-3) 196-199 2004年2月

    出版者・発行元:ELSEVIER SCIENCE BV

    DOI: 10.1016/S0169-4332(03)00916-4  

    ISSN:0169-4332

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    Dielectric property of a composition-spread LiNb1-xTaxO3 thin film, fabricated by the combinatorial pulsed-laser deposition (PLD) method, was systematically characterized by the scanning microwave microscope (SmuM). Measured frequency shift showed a broad maximum around x = 0.2-0.5, and gradually decreased with x, resulting in a lower dielectric constant in the LiTaO3 side compared to the LiNbO3 side. The trend of frequency shift has been revealed to possess a strong correlation with the sharpness of XRD peak, suggesting that lowering of dielectric constant is principally brought about by the degradation of crystallinity. (C) 2003 Published by Elsevier B.V.

  195. Combinatorial synthesis and luminescent characteristics of RECa4O(BO3)(3) epitaxial thin films 査読有り

    H Kubota, R Takahashi, TW Kim, T Kawazoe, M Ohtsu, N Arai, M Yoshimura, H Nakao, H Furuya, Y Mori, T Sasaki, Y Matsumoto, H Koinuma

    APPLIED SURFACE SCIENCE 223 (1-3) 241-244 2004年2月

    出版者・発行元:ELSEVIER SCIENCE BV

    DOI: 10.1016/j.apsusc.2003.10.014  

    ISSN:0169-4332

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    A series of RECa4O(BO3)(3) (RECOB) thin films (RE = Rare earth elements) was fabricated on ultrasmooth GdCOB (0 1 0) substrates by laser molecular beam epitaxy (MBE) method to explore the optimal growth conditions and to evaluate the luminescent properties. The growing surface of the film on a temperature gradient substrate was diagnosed with scanning reflection high energy electron diffraction (S-RHEED) system for quickly specifying optimum growth temperature and its dependence of rare earth element. The lowest temperature for epitaxial film growth was defined by the appearance of streak pattern in RHEED and it reflected the lattice matching with the substrate. TbCCB and EuCOB emitted respectively very bright green (543 nm) and red (611 nm) light, indicating that they are promising new phosphors. It is noteworthy that we could detect a remarkably strong red emitting region in the EuCOB-ScCOB-PrCOB ternary composition spread library.(C) 2003 Elsevier B.V. All rights reserved.

  196. Combinatorial fabrication and characterization of ferromagnetic Ti-Co-O system 査読有り

    M Murakami, Y Matsumoto, M Nagano, T Hasegawa, M Kawasaki, H Koinuma

    APPLIED SURFACE SCIENCE 223 (1-3) 245-248 2004年2月

    出版者・発行元:ELSEVIER SCIENCE BV

    DOI: 10.1016/S0169-4332(03)00906-1  

    ISSN:0169-4332

    eISSN:1873-5584

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    TiO2-CoO binary compositional spread thin films were grown on a LaSrA1O(4)(0 0 1) (LASO) single crystal substrate at temperatures gradient from 550 to 750 degreesC. The ambient was fixed at an oxygen pressure between 5 x 10(-5) and 5 x 10(-7) Torr during the deposition. Scanning superconducting quantum interference device microscope was used as a high throughput screening of magnetic properties in the combinatorial libraries. X-ray diffraction (XRD) was used as structural characterization. From the XRD measurements, c-axis oriented anatase peaks were observed up to Co contents around 50%. Around this Co content, CoTiO3 peaks have maximum intensity and CoO peak appeared at higher Co content. The film magnetization was increasing with decreasing of oxygen pressure at the deposition. The region, in which magnetic domain structure was observed, agrees well with film conductive region. (C) 2003 Elsevier B.V. All rights reserved.

  197. Development of a new combinatorial mask for addressable ternary phase diagramming: application to rare earth doped phosphors 査読有り

    R Takahashi, H Kubota, T Tanigawa, M Murakami, Y Yamamoto, Y Matsumoto, H Koinuma

    APPLIED SURFACE SCIENCE 223 (1-3) 249-252 2004年2月

    出版者・発行元:ELSEVIER SCIENCE BV

    DOI: 10.1016/S0169-4332(03)00925-5  

    ISSN:0169-4332

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    We report on the computer-aided design of a novel mask for the addressable ternary phase diagram to serve a quick screening of multi-component functional materials. Masking patterns were optimized to make a triangular ternary diagram with each composition changed from 0 to 100% by simulating the deposition process under the condition of synchronous control of the mask motion, target exchange, and laser pulses. Fabrication of a ternary M0.01Y1.99O3 (M = Eu, Tm, Tb) phosphor material demonstrates of the direct mapping relationship between the film composition and its cathode luminescence (CL) property.(C) 2003 Elsevier B.V. All rights reserved.

  198. Sr2Rh1-xRuxO4 (0 &lt;= x &lt;= 1) composition-spread film growth on a temperature-gradient substrate by pulsed laser deposition 査読有り

    T Wakisaka, T Koida, Y Matsumoto, K Itaka, H Koinuma

    APPLIED SURFACE SCIENCE 223 (1-3) 264-267 2004年2月

    出版者・発行元:ELSEVIER SCIENCE BV

    DOI: 10.1016/j.apsusc.2003.10.013  

    ISSN:0169-4332

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    K2NiF4-type Sr2Rh1-xRuxO4 (0 less than or equal to X less than or equal to 1) composition-spread films were fabricated on (LaA1O(3))(0.3)-(Sr2AlTaO6)(0.7) (LSAT) substrate by using the combinatorial PLD method. From a temperature spread combinatorial deposition, Sr2RhO4 (x = 0) is found to grow epitaxially only in a narrow temperature range, i.e. 735 +/- 115 degreesC. By varying the composition and temperature along x and y axes of the substrate, respectively, two-dimensional (2D) libraries of Sr2Rh1-xRuxO4 (0 less than or equal to X less than or equal to 1) films were fabricated to map the growth temperature dependence of film crystallinity for the full range of x = 0-1. The optimum epitaxial growth temperature exhibited clear dependence on the compositional variation, x. From measurements of the electric conductivity of the films, metal-insulator-metal transitions were detected as the compositional parameter x increased from 0 to 1. (C) 2003 Elsevier B.V. All rights reserved.

  199. High-throughput screening of flux materials for single crystal growth by combinatorial pulsed laser deposition 査読有り

    R Takahashi, T Tanigawa, Y Yamamoto, Y Yonezawa, Y Matsumoto, H Koinuma

    COMBINATORIAL AND ARTIFICIAL INTELLIGENCE METHODS IN MATERIALS SCIENCE II 804 69-74 2004年

    出版者・発行元:MATERIALS RESEARCH SOCIETY

    ISSN:0272-9172

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    We propose a new concept and method for high throughput screening of flux materials used in the bulk single crystal growth. The concept of our tri-phase epitaxy has been generalized as the flux-mediated epitaxy with the aid of quick optimization of flux materials in the combinatorial thin-film technology. Here, we report on the successful discovery of a new flux composition of Bi-Ti-Cu-O for the growth of high-quality Bi4Ti3O12 bulk crystal and thin film.

  200. Design of combinatorial shadow masks for complete ternary-phase diagramming of solid state materials 査読有り

    R Takahashi, H Kubota, M Murakami, Y Yamamoto, Y Matsumoto, H Koinuma

    JOURNAL OF COMBINATORIAL CHEMISTRY 6 (1) 50-53 2004年1月

    出版者・発行元:AMER CHEMICAL SOC

    DOI: 10.1021/cc030038i  

    ISSN:1520-4766

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    We report on a novel mask design for the combinatorial synthesis of a ternary composition spreads library, which allows such libraries to be deposited through a series of simple masks on a rotatable mount. This eliminates the use of complicated actuation of a heated substrate. In our configuration, this design leads to a standard linear phase diagram by varying the growth rate of each constituent nearly linearly from 0 to 100% at a triangular area on the substrate. Film growth occurs as a series of cycles in which one molecular layer of the material is deposited over the entire area of the spread by a synchronization of the mask movement, target exchange, and laser pulses. The technique has been applied to the synthesis of photoluminescent TbCa4O(BO3)(3)-ScCa4O(BO3)(3)-PrCa4O(BO3)(3), demonstrating its value for the mapping of direct relationship between composition and the light-emitting property.

  201. Temperature dependence of absorption spectra in anatase TiO2 epilayers 査読有り

    T Makino, Y Segawa, M Kawasaki, Y Matsumoto, H Koinuma, M Murakami, R Takahashi

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN 72 (10) 2696-2697 2003年10月

    出版者・発行元:PHYSICAL SOC JAPAN

    DOI: 10.1143/JPSJ.72.2696  

    ISSN:0031-9015

  202. Combinatorial investigation of spintronic materials 査読有り

    Y Matsumoto, H Koinuma, T Hasegawa, Takeuchi, I, F Tsui, YK Yoo

    MRS BULLETIN 28 (10) 734-739 2003年10月

    出版者・発行元:MATERIALS RESEARCH SOCIETY

    DOI: 10.1557/mrs2003.215  

    ISSN:0883-7694

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    High-throughput synthesis and characterization techniques have been effective in discovering new materials and performing rapid mapping of phase diagrams. The application of the combinatorial strategy to explore doped transition-metal oxides has led to the discovery of a transparent room-temperature ferromagnetic oxide in Co-doped anatase TiO2. The discovery has triggered a wave of studies into other metal oxide systems in pursuit of diluted magnetic semiconductors. In this article, we describe recent combinatorial studies of magnetic transition-metal oxides, germanium-based magnetic semiconductors, and Heusler alloys.

  203. A high-resolution transmission electron microscopy investigation of the microstructure of TiO2 anatase film deposited on LaAlO3 and SrTiO3 substrates by laser ablation 査読有り

    M Zhu, T Chikyow, P Ahmet, T Naruke, M Murakami, Y Matsumoto, H Koinuma

    THIN SOLID FILMS 441 (1-2) 140-144 2003年9月

    出版者・発行元:ELSEVIER SCIENCE SA

    DOI: 10.1016/S0040-6090(03)00939-8  

    ISSN:0040-6090

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    In the present work the microstructure of anatase TiO2 film deposited on LaAlO3 and SrTiO3 substrates by pulse laser ablation was investigated using high-resolution transmission electron microscopy (HRTEM) and electron diffraction analysis. The experimental observations reveal the structural features of the interface between the film and the substrate and three main types of crystal defects in the anatase TiO2 film. Observation of the interface showed that the anatase was epitaxially grown on the substrates although defects, such as dislocations and distorted regions can be observed near the interface. Using HRTEM observation several types of defects were found in the deposited film. These defects include both dislocations with the (112) and (001) planes as extra atom planes and micro-twins with the (112) plane as the twin plane. (C) 2003 Elsevier B.V. All rights reserved.

  204. Novel In-Gap Spin State in Zn-Doped [Formula presented] 査読有り

    H. Kimura, M. Kofu, Y. Matsumoto, K. Hirota

    Physical Review Letters 91 (6) 2003年8月5日

    DOI: 10.1103/PhysRevLett.91.067002  

    ISSN:1079-7114 0031-9007

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    Low-energy spin excitations of [Formula presented] were studied by neutron scattering. In [Formula presented], the incommensurate magnetic peaks show a well-defined “spin gap” below [Formula presented]. The magnetic signals at [Formula presented] decrease below [Formula presented] for [Formula presented], also suggesting the gap opening. At lower temperatures, however, the signal increases again, implying a novel in-gap spin state. In [Formula presented], the spin gap vanishes and elastic magnetic peaks appear. These results clarify that doped Zn impurities induce the novel in-gap state, which becomes larger and more static with increasing Zn. © 2003 The American Physical Society.

  205. Synthesis and characterization of single crystalline REBa2Cu3O7-y thin film grown by tri-phase epitaxy 査読有り

    KS Yun, Y Matsumoto, S Arisawa, Y Takano, A Ishii, T Hatano, K Togano, M Kawasaki, H Koinuma

    IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY 13 (2) 2813-2816 2003年6月

    出版者・発行元:IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC

    DOI: 10.1109/TASC.2003.812013  

    ISSN:1051-8223

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    We report on the successful fabrication of single crystalline thin films of REBa2Cu3O7-y (RE123, RE: rare earth elements) using a novel process of Tri-Phase Epitaxy. This method is based on the application of pulsed laser deposition (PLD) under appropriate compositions and conditions predetermined from the relevant thermodynamic phase diagram. Prior to the growth of the film, a liquid phase, film (near-eutectic composition of BaO-CuO) is intentionally formed. The RE123 single crystalline thin film is grown at the liquid-solid interface. The consumed RE123 in the liquid layer is compensated by the laser-ablated vapor and the composition of the liquid phase is kept constant. Thermodynamic equilibrium can be maintained at the liquid-solid film boundary while preserving the benefit of intrinsic stoichiometry control offered by the PLD technique. Atomically smooth Him surface and single crystalline nature of film was verified by combined characterization methods of x-ray diffraction, atomic force microscopy and transmission electron microscopy.

  206. Recognition of the atomic terminating layer in perovskite oxide substrates by reflection high energy electron diffraction 査読有り

    R Takahashi, Y Matsumoto, H Koinuma

    JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS 42 (4A) L389-L390 2003年4月

    出版者・発行元:INST PURE APPLIED PHYSICS

    DOI: 10.1143/JJAP.42.L389  

    ISSN:0021-4922

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    The chemical surface structure in perovskite oxides has been identified by monitoring the oscillation intensity of reflection high energy electron diffraction patterns during initial growth of MO (M=Sr, Ba) films on the perovskite substrate. This successful analysis technique is demonstrated for the film growth on A and B-site oxides terminated ABO(3) substrates. Epitaxial growth of MO thin films is dominated by chemical interaction between the growing lattice and the underlying atomic layer to follow the crystal habit of forming a more stable layer unit cell. This simple technique can be used as a substitute to relevant physical techniques such as coaxial impact-collision ion scattering spectroscopy and friction force microscopy that are currently used techniques to determine the termination layer.

  207. Synthesis of epitaxial Y-type magnetoplumbite thin films by quick optimization with combinatorial pulsed laser deposition 査読有り

    Ohkubo, I, Y Matsumoto, K Ueno, T Chikyow, M Kawasaki, H Koinuma

    JOURNAL OF CRYSTAL GROWTH 247 (1-2) 105-109 2003年1月

    出版者・発行元:ELSEVIER SCIENCE BV

    DOI: 10.1016/S0022-0248(02)01793-1  

    ISSN:0022-0248

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    Y-type magnetoplumbite (Ba2Co2Fe12O22:Co2Y) epitaxial thin films with such a huge lattice parameter as 43.5 Angstrom have been synthesized for the first time. Combinatorial thin film technology was successfully employed to eliminate an impurity phase in the film by quickly optimizing such reaction parameters as the deposition temperature and the thickness of pre-deposition of CoO layer. The coupling of combinatorial pulsed laser deposition and subsequent concurrent X-ray diffraction, both of which we have developed, is a promising way to high throughput optimization of thin film growth and properties. (C) 2002 Elsevier Science B.V. All rights reserved.

  208. Metal-insulator-metal transition in Sr2Rh1-xRuxO4(0 &lt;= x &lt;= 1) 査読有り

    T Koida, T Wakisaka, K Itaka, H Koinuma, Y Matsumoto

    APPLIED PHYSICS LETTERS 81 (26) 4955-4957 2002年12月

    出版者・発行元:AMER INST PHYSICS

    DOI: 10.1063/1.1530372  

    ISSN:0003-6951

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    Structural and electrical properties of c-axis oriented epitaxial Sr2Rh1-xRuxO4 (0less than or equal toxless than or equal to1) films were systematically investigated. The composition-spread films were fabricated on a temperature gradient (LaAlO3)(0.3)(Sr2AlTaO6)(0.7) substrate to quickly optimize the growth temperature for a high-quality crystalline film having each composition (x). An anomalous c-axis length dependence on x was observed, and it was accompanied by a distinct change in electric property, that is, a metal-insulator-metal transition. (C) 2002 American Institute of Physics.

  209. Effect of A-site cation ordering on the magnetoelectric properties in [(LaMnO<inf>3</inf>)<inf>m</inf>/(SrMnO<inf>3</inf>)<inf>m</inf>]<inf>n</inf> artificial superlattices

    T. Koida, M. Lippmaa, T. Fukumura, K. Itaka, Y. Matsumoto, M. Kawasaki, H. Koinuma

    Physical Review B - Condensed Matter and Materials Physics 66 (14) 1444181-1444186 2002年10月1日

    ISSN:0163-1829

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    In order to evaluate the effect of charge transfer and/or charge ordering in La1-xSrxMnO3 on the magnetic and transport properties, a library of [(LaMnO3)m/(SrMnO3)m]n superlattices have been fabricated by the combinatorial pulsed laser deposition method. The properties of superlattices were found to depend strongly on the periodicity m; superlattices of m≤4 behaved like a solid solution La0.5Sr0.2MnO3 film, while the superlattices of m>4 were significantly different from the solid solution. These superlattices exhibited a higher resistivity and lower Curie temperature than m≤4 superlattices. The results indicate that the properties of the superlattices are dominated not only by the magnetic interaction between the superlattice constituents but also by carrier (eg electrons) transfer thorough the superlattice interface. The contribution of carrier transfer is supported by the magnetoelectric properties of another library of [(La0.8Sr0.2 MnO3)8/(La0.2 Sr0.8MnO3)m]12 superlattices. The A-site cation order can change both effective carrier concentration and magnetic interaction.

  210. Growth of NdBa2Cu3O7-y single crystal thin films by tri-phase epitaxy 査読有り

    KS Yun, BD Choi, JH Song, Y Matsumoto, P Ahmet, T Chikyow, M Kawasaki, H Koinuma

    PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS 378 (2) 1202-1208 2002年10月

    出版者・発行元:ELSEVIER SCIENCE BV

    DOI: 10.1016/S0921-4534(02)01689-1  

    ISSN:0921-4534

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    We report on the successful fabrication of single crystal thin films of NdBa2CU3O7-y (Nd123) using the tri-phase epitaxy (TPE) approach. This method is based on application of pulsed laser deposition under appropriate compositions and conditions predetermined from the relevant thermodynamic phase diagram. Thermodynamic equilibrium is maintained while maintaining intrinsic stoichiometry control offered by the pulsed laser deposition technique. Uniform atomically smooth single crystalline nature of film was verified by combined characterization methods of X-ray diffraction, atomic force microscopy and transmission electron microscopy. Here we report on the conceptual details of TPE process as well as on the characterization of the Nd123 thin films. (C) 2002 Elsevier Science B.V. All rights reserved.

  211. Effect of A-site cation ordering on the magnetoelectric properties in [(LaMnO3)(m)/(SrMnO3)(m)](n) artificial superlattices 査読有り

    T Koida, M Lippmaa, T Fukumura, K Itaka, Y Matsumoto, M Kawasaki, H Koinuma

    PHYSICAL REVIEW B 66 (14) 144418 2002年10月

    出版者・発行元:AMERICAN PHYSICAL SOC

    DOI: 10.1103/PhysRevB.66.144418  

    ISSN:1098-0121

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    In order to evaluate the effect of charge transfer and/or charge ordering in La1-xSrxMnO3 on the magnetic and transport properties, a library of [(LaMnO3)(m)/(SrMnO3)(m)](n) superlattices have been fabricated by the combinatorial pulsed laser deposition method. The properties of superlattices were found to depend strongly on the periodicity m; superlattices of mless than or equal to4 behaved like a solid solution La0.5Sr0.5MnO3 film, while the superlattices of m&gt;4 were significantly different from the solid solution. These superlattices exhibited a higher resistivity and lower Curie temperature than mless than or equal to4 superlattices. The results indicate that the properties of the superlattices are dominated not only by the magnetic interaction between the superlattice constituents but also by carrier (e(g) electrons) transfer thorough the superlattice interface. The contribution of carrier transfer is supported by the magnetoelectric properties of another library of [(La0.8Sr0.2MnO3)(8)/(La0.2Sr0.8MnO3)(m)](12) superlattices. The A-site cation order can change both effective carrier concentration and magnetic interaction.

  212. Quick optimization of Y-type magnetoplumbite thin films growth by combinatorial pulsed laser deposition technique 査読有り

    Ohkubo, I, Y Matsumoto, K Itaka, T Hasegawa, K Ueno, M Ohtani, M Kawasaki, H Koinuma

    APPLIED SURFACE SCIENCE 197 312-315 2002年9月

    出版者・発行元:ELSEVIER SCIENCE BV

    DOI: 10.1016/S0169-4332(02)00388-4  

    ISSN:0169-4332

    eISSN:1873-5584

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    Quick growth optimization of complex oxide, Y-type magnetoplumbite (Ba2Co2Fe12O22 (Co2Y)) thin films is demonstrated by using combinatorial thin film technology. Planning a Coo buffer layer on MgAl2O4(1 1 1) substrate was found to be very effective for preventing the phase separation of Co deficient impurity (BaFe2O4) and forming the desired Co2Y phase. The combinatorial pulsed laser deposition and subsequent concurrent X-ray diffraction facilitate the production of Y-type magnetoplumbite thin film in a single phase. (C) 2002 Elsevier Science B.V All rights reserved.

  213. Combinatorial fabrication and cathodoluminescence properties of composition spread MHfO3 : Tm3+ (M = Ca, Sr and Ba) films 査読有り

    N Arai, TW Kim, H Kubota, Y Matsumoto, H Koinuma

    APPLIED SURFACE SCIENCE 197 402-405 2002年9月

    出版者・発行元:ELSEVIER SCIENCE BV

    DOI: 10.1016/S0169-4332(02)00349-5  

    ISSN:0169-4332

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    A series of MHfO3:Tm3+ (M = Ca, Sr and Ba) films were fabricated on SrTiO3 (0 0 1) substrate by using combinatorial pulsed laser deposition (PLD) technique. Their crystal structures and luminescence properties were characterized by the concurrent X-ray diffraction (CXRD) and by the cathodoluminescence (CL) using 5 kV electron beam, respectively. By monitoring the reflection high energy electron diffraction (RHEED) intensity oscillation, the growth of MHfO3:Tm3+ films were optimized to proceed in a epitaxial layer-by-layer fashion. Different from bulk powders, which had the highest CL intensity in SrHfO3:Tm3+, the composition spread film of Sr1-xCaxHfO3:Tm3+ (x = 0-1) exhibited the highest CL intensity at x = 0.7 rather than SrHfO3:Tm3+ (x = 0). This anomalous behavior in the films is discussed in view of the stress effect from the substrate. (C) 2002 Elsevier Science B.V. All rights reserved.

  214. Re-evaporation effect on the surface morphology of GdxY1-xCa4O(BO3)(3) films grown by combinatorial laser molecular-beam epitaxy 査読有り

    TW Kim, N Arai, H Kubota, H Koinuma, Y Matsumoto, M Yoshimura, H Furuya, H Nakao, Y Mori, T Sasaki

    APPLIED SURFACE SCIENCE 197 406-410 2002年9月

    出版者・発行元:ELSEVIER SCIENCE BV

    DOI: 10.1016/S0169-4332(02)00350-1  

    ISSN:0169-4332

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    We have found unusual re-evaporation effect on the surface morphology of GdxY1-xCa4O(BO3)(3) (GdxY1-xCOB) films grown by combinatorial laser molecular-beam epitaxy. The surface morphologies of the GdxY1-xCOB films grown on the atomically flat (0 1 0) GdCa4O(BO3)(3) (GdCOB) substrates were strongly dependent on the deposition conditions such as substrate temperature and laser repetition rate. Decreasing the substrate temperature and/or increasing the laser repetition rate improved the surface morphology of the film since at such deposition conditions, re-evaporation which may make film surface rough could be effectively restrained. GdxY1-xCOB film grown at 500 degreesC and 4 Hz exhibited the ultra-smooth surface like that of the atomically smooth (0 1 0) GdCOB substrate. Under such conditions, intensity monitoring of reflection high-energy electron diffraction revealed the layer-by-layer growth of the film. Using this regulated growth behavior of the films we have successfully fabricated such nano-structured films as [GdCOB/YCa4O(BO3)(3)] superlattices. (C) 2002 Elsevier Science B.V. All rights reserved.

  215. Combinatorial optimization oxide films by the carrousel of atomically controlled growth for type laser molecular beam epitaxy 査読有り

    R Takahashi, Y Matsumoto, H Koinuma, M Lippmaa, M Kawasaki

    APPLIED SURFACE SCIENCE 197 532-535 2002年9月

    出版者・発行元:ELSEVIER SCIENCE BV

    DOI: 10.1016/S0169-4332(02)00331-8  

    ISSN:0169-4332

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    We have developed a new combinatorial technique, "carrousel deposition" for the atomically controlled growth of oxide films under in situ diagnostics of surface reaction with reflection high energy electron diffraction (RHEED). In this technique, a sequential fabrication of eight different films is performed in one experiment, enabling quick optimization of the growth conditions with the assistance of RHEED monitoring. Thus, we succeeded in the one lot optimization of the layer-by-layer SrO and BaO film growth on the B-site (TiO2) terminated SrTiO3(0 0 1) substrate. Furthermore, the characteristic, crystal habit in the initial growth of MO atomic layers on the SrTiO3 substrate was elucidated to be dominated by the topmost atomic layer of the substrate or film and the atomic layer to be formed on it. (C) 2002 Elsevier Science B.V. All rights reserved.

  216. Fabrication of HTSC single crystalline thin films by tri-phase epitaxy 査読有り

    R Takahashi, YK Sung, Y Matsumoto, M Kawasaki, T Chikyow, H Koinuma

    JOURNAL OF THE JAPAN INSTITUTE OF METALS 66 (4) 284-288 2002年4月

    出版者・発行元:JAPAN INST METALS

    ISSN:0021-4876

    eISSN:1880-6880

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    A high-Tc superconducting (HTSC) thin film with single crystal quality and atomically flat surface is a basic requirement for the fabrication of HTSC electronic devices. Despite extensive effort since the discovery of high-Tc superconductivity, this requirement has not been fully satisfied yet. Based on our experience on HTSC thin film growth, we proposed a novel fabricating method of single crystal RBa2Cu3O7-delta(R=Y, Nd) thin films that are free from grain boundaries and have atomic scale surface smoothness. This method was devised in view of the thermodynamic phase diagram of RBa2Cu3O7-delta and the characteristics of vapor phase epitaxy (VPE). Since gas, liquid and solid phases are involved in this film growth, it is denoted Tri-Phase Epitaxy (TPE). Giant single crystal grains, verified by X-ray diffraction and transmission electron microscopy (TEM), should provide a big advantage for the use of these films in such applications as high frequency transmission lines and superconducting tunnel junctions.

  217. Development of scanning microwave microscope with a lumped-constant resonator probe for high-throughput characterization of combinatorial dielectric materials 査読有り

    N Okazaki, H Odagawa, Y Cho, T Nagamura, D Komiyama, T Koida, H Minami, P Ahmet, T Fukumura, Y Matsumoto, M Kawasaki, T Chikyow, H Koinuma, T Hasegawa

    APPLIED SURFACE SCIENCE 189 (3-4) 222-226 2002年4月

    出版者・発行元:ELSEVIER SCIENCE BV

    DOI: 10.1016/S0169-4332(01)01013-3  

    ISSN:0169-4332

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    A scanning microwave microscope (SmuM) for combinatorial characterization of dielectric materials has been developed using a lumped-constant resonator probe. The probe consists of a commercially available microwave oscillator module equipped with a thin conducting needle and an outer conductor ring. The capacitance between needle and ring changes with the dielectric constant of the sample just beneath the needle, which can be detected as a frequency shift of the resonator with high accuracy. The frequency shift values measured for various standard samples lay on a master curve theoretically predicted, which guarantees the quantitative evaluation of the dielectric constant. Applicability of the present system to the characterization of combinatorial samples is demonstrated. (C) 2002 Elsevier Science B.V. All rights reserved.

  218. High-throughput optical characterization for the development of a ZnO-based ultraviolet semiconductor-laser 査読有り

    T Makino, CH Chia, Y Segawa, M Kawasaki, A Ohtomo, K Tamura, Y Matsumoto, H Koinuma

    APPLIED SURFACE SCIENCE 189 (3-4) 277-283 2002年4月

    出版者・発行元:ELSEVIER SCIENCE BV

    DOI: 10.1016/S0169-4332(01)01001-7  

    ISSN:0169-4332

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    We have developed a concurrent method of optical measurements using optical fiber bundles and charge coupled devices (CCDs), especially equipped for application to combinatorial samples. This approach can also be used for experiments performed at cryogenic temperatures. This combinatorial characterization method will be explained in detail. The dependence of the optical properties in combinatorial samples of ZnO/(Mg,Zn)O multi-quantum wells prepared by laser molecular-beam epitaxy upon well width was found to be smooth compared with the samples grown by a conventional method. The use of lattice-matched ScAlMgO4 substrates greatly improved the properties of quantum wells and, as a result, a bright photoluminescence (PL) of free excitons could be observed even at room temperature. In addition, the PL could be tuned in the energy range 3.3-3.6 eV by choosing the appropriate barrier height and well layer thickness. (C) 2002 Elsevier Science B.V. All rights reserved.

  219. Structural control and combinatorial doping of titanium dioxide thin films by laser molecular beam epitaxy 査読有り

    Y Matsumoto, A Murakami, T Hasegawa, T Fukumura, M Kawasaki, P Ahmet, K Nakajima, T Chikyow, H Koinuma

    APPLIED SURFACE SCIENCE 189 (3-4) 344-348 2002年4月

    出版者・発行元:ELSEVIER SCIENCE BV

    DOI: 10.1016/S0169-4332(01)01025-X  

    ISSN:0169-4332

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    Structural control of titanium dioxide, TiO2, thin films was achieved by the selection of appropriate substrates. The rutile phase of the TiO2 thin film was grown on alpha-Al2O3(0 0 0 1) substrate, while the anatase phase was on SrTiO3(0 0 1) and LaAO(3)(0 0 1) substrates. The crystallinity of the anatase films has been much improved by the use of the LaAlO3(0 0 1) substrate. The combinatorial doping with 3d transition metals in the TiO2 thin films was carried out for the rutile and anatase films in much shorter time than the conventional one-by-one process, leading to the discovery of transparent ferromagnetism in the Co-doped anatase film. (C) 2002 Elsevier Science B.V. All rights reserved.

  220. Combinatorial optimization of atomically controlled growth for oxide films by the carrousel type laser molecular beam epitaxy 査読有り

    Takahashi R, Matsumoto Y, Koinuma H, Lippmaa M, Kawasaki M, Takeuchi I, Newsam JM, Wille LT, Amis EJ

    700 13-18 2002年

    DOI: 10.1016/S0169-4332(02)00331-8  

    ISSN:0169-4332

  221. Combinatorial optimization of atomically controlled growth for oxide films by the carrousel type laser molecular beam epitaxy 査読有り

    R Takahashi, Y Matsumoto, H Koinuma, M Lippmaa, M Kawasaki

    COMBINATORIAL AND ARTIFICIAL INTELLIGENCE METHODS IN MATERIALS SCIENCE 700 13-18 2002年

    出版者・発行元:MATERIALS RESEARCH SOCIETY

    ISSN:0272-9172

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    A new combinatorial pulsed laser deposition system has been developed for rapid optimization of epitaxial growth process by using a carrousel type masking plate. Under in-situ monitoring of growing surface with reflection high energy electron diffraction, eight films with different compositions or preparation parameters can be fabricated on a single substrate. By using this system, we have succeeded in the one lot optimization of YBa2Cu3O7-d(YBCO), PrGaO3, SrO and BaO film growths on the B-site (TiO2) terminated SrTiO3(001) substrates. Key results from these experiments include the high sensitivity of YBCO film crystallinity to the laser focusing as well as of growth behavior of epitaxial SrO and BaO films to the crystal habit with the underlying atomic layers.

  222. Growth dynamics of the epitaxial SrO film on SrTiO3(001) 査読有り

    R Takahashi, Y Matsumoto, T Ohsawa, M Lippmaa, M Kawasaki, H Koinuma

    JOURNAL OF CRYSTAL GROWTH 234 (2-3) 505-508 2002年1月

    出版者・発行元:ELSEVIER SCIENCE BV

    DOI: 10.1016/S0022-0248(01)01741-9  

    ISSN:0022-0248

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    The initial growth of SrO thin films was investigated by in-situ reflection high-energy electron diffraction (RHEED) and scanning tunneling microscope (STM). When SrO was deposited under epitaxial growth conditions on B-site terminated SrTiO3(0 0 1) substrate, the first layer reacted with the B-site layer to grow as A site layer of the perovskite. Once this A-site layer was completed, the subsequent SrO layers were grown in a layer-by-layer manner. The basic unit for layer-by-layer growth is a rock-salt unit cell. The growth mode of SrO on SrTiO3(0 0 1) is discussed in relation to the crystal lattice habit. (C) 2002 Elsevier Science B.V. All rights reserved.

  223. Vapor-liquid-solid tri-phase pulsed-laser epitaxy of RBa2Cu3O7-y single-crystal films 査読有り

    KS Yun, BD Choi, Y Matsumoto, JH Song, N Kanda, T Itoh, M Kawasaki, T Chikyow, P Ahmet, H Koinuma

    APPLIED PHYSICS LETTERS 80 (1) 61-63 2002年1月

    出版者・発行元:AMER INST PHYSICS

    DOI: 10.1063/1.1432111  

    ISSN:0003-6951

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    We report on the fabrication of single-crystalline thin films of RBa2Cu3O7-y (R: rare-earth element, R123) using an approach of vapor-liquid-solid tri-phase epitaxy. This method is based on application of pulsed-laser deposition under appropriate compositions and conditions predetermined from the relevant thermodynamic phase diagram. The laser-ablated gases of R, Ba, and Cu, and their oxides dissolve into a liquid Ba3Cu5Ox (3BaCuO(2)+2CuO) layer placed on the film/substrate surface, penetrate to reach the liquid-solid interface with a seed R123, and are condensed into the solid R123 phase under a quasiequilibrium state. The uniform single-crystalline nature of the film was verified by x-ray diffraction, atomic-force microscopy, and transmission electron microscopy by the observation of giant grain size and atomic-scale surface smoothness. (C) 2002 American Institute of Physics.

  224. Pulsed laser epitaxy and magnetic properties of single phase Y-type magnetoplumbite thin films 査読有り

    Ohkubo, I, Y Matsumoto, T Hasegawa, K Ueno, K Itaka, P Ahmet, T Chikyow, M Kawasaki, H Koinuma

    JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS 40 (12B) L1343-L1345 2001年12月

    出版者・発行元:INST PURE APPLIED PHYSICS

    DOI: 10.1143/JJAP.40.L1343  

    ISSN:0021-4922

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    Single phase. c-axis oriented thin films of Y-type magnetoplumbite (Ba2Co2Fe12O22; Co2Y) with a very large c-axis length as 43.5 Angstrom were grown successfully by pulsed laser deposition technique. The key points were high temperature deposition and the use of CoO buffer layer inserted between the film and MgAl2O4(1 1 1) substrate. From the transmission electron microscope (TEM) analysis, the CoO buffer layer was consumed to make an atomically sharp interface of Co2Y and Substrate. Superconducting quantum interference device magnetometer was used to verify the high magnetic properties of the epitaxial thin films.

  225. Ferromagnetism in co-doped TiO2 rutile thin films grown by laser molecular beam epitaxy 査読有り

    Y Matsumoto, R Takahashi, M Murakami, T Koida, XJ Fan, T Hasegawa, T Fukumura, M Kawasaki, SY Koshihara, H Koinuma

    JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS 40 (11B) L1204-L1206 2001年11月

    出版者・発行元:INST PURE APPLIED PHYSICS

    DOI: 10.1143/JJAP.40.L1204  

    ISSN:0021-4922

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    Epitaxial TiO2 rutile films were fabricated on alpha -Al2O3 (10 (1) over bar2) substrate in the layer-by-layer fashion by laser molecular beam epitaxy. Ablation with a Co-doped TiO2 target produced single phase of rutile film with the concentration of Co between 0 and 5%. Some ferromagnetic domain structures were observed in CoxTi1-xO2 rutile films by a scanning superconducting quantum interference device microscope at 3 to 90 K. The magnetic hysteresis could also be observed even at room temperature with a magnetic moment of similar to1 muB/Co atom.

  226. Concurrent x-ray diffractometer for high throughput structural diagnosis of epitaxial thin films 査読有り

    M Ohtani, T Fukumura, M Kawasaki, K Omote, T Kikuchi, J Harada, A Ohtomo, M Lippmaa, T Ohnishi, D Komiyama, R Takahashi, Y Matsumoto, H Koinuma

    APPLIED PHYSICS LETTERS 79 (22) 3594-3596 2001年11月

    出版者・発行元:AMER INST PHYSICS

    DOI: 10.1063/1.1415402  

    ISSN:0003-6951

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    We have developed a concurrent x-ray diffractometer that concurrently measures spatially resolved x-ray diffraction (XRD) spectra of epitaxial thin films integrated on a substrate. A convergent x-ray is focused into stripe on a substrate and the diffracted beam is detected with a two-dimensional x-ray detector. The obtained snapshot image represents a mapping of XRD intensity with the axes of the diffraction angle and the position in the sample. In addition to the parallel XRD measurements of thin films with various compositions and structures, two-dimensional spatial mapping of XRD peak with a resolution of similar to 100 mum is demonstrated. This technique will provide us a high throughput characterization method of various devices composed of epitaxial films. (C) 2001 American Institute of Physics.

  227. Atomic-scale surface control and second-harmonic generation in GdxY(1-x)Ca4O(BO3)3 thin films grown by combinatorial laser molecular-beam epitaxy 査読有り

    TW Kim, N Arai, H Koinuma, Y Matsumoto, M Yoshimura, H Furuya, H Nakao, Y Mori, T Sasaki

    APPLIED PHYSICS LETTERS 79 (12) 1783-1785 2001年9月

    出版者・発行元:AMER INST PHYSICS

    DOI: 10.1063/1.1402964  

    ISSN:0003-6951

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    We studied the atomic-scale, growth control and second-harmonic generation (SHG) properties of GdxY1-xCa4O(BO3)(3) thin films. Combinatorial laser molecular-beam epitaxy was employed to optimize the growth conditions of the film. Ultrasmooth GdxY1-xCa4O(BO3)(3) thin films with step-and-terrace structure were obtained by using atomically controlled GdCa4O(BO3)(3) substrates. The dependence of SHG intensity on the fundamental wave polarization angle was studied for the epitaxial film on (010) GdCa4O(BO3)(3) substrate in comparison for the randomly oriented film on (0001) sapphire substrate. It was found that only the epitaxially grown film clearly exhibited a fourfold SHG intensity showing type-II phase-matching direction. (C) 2001 American Institute Of Physics.

  228. Laser molecular beam epitaxy of high-quality GdxY1-xCa4O(BO3)(3) thin films 査読有り

    TW Kim, N Arai, Y Matsumoto, M Yoshimura, H Furuya, Y Mori, T Sasaki, H Koinuma

    JOURNAL OF CRYSTAL GROWTH 229 (1) 208-211 2001年7月

    出版者・発行元:ELSEVIER SCIENCE BV

    DOI: 10.1016/S0022-0248(01)01122-8  

    ISSN:0022-0248

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    High-quality epitaxial GdxY1-xCa4O(BO3)(3) thin films were successfully fabricated on atomically flat GdCa4O(BO3)(3) (0 1 0) single crystal substrates by laser molecular beam epitaxy from a sintered GdxY1-xCa4O(BO3)(3) (x = 0.28) target. It was found that the film surface morphology strongly depends on the substrate temperature and the laser repetition rate. The film crystallinity was highly dependent of substrate materials. Second-harmonic generation (SHG) was observed on the epitaxial GdxY1-xCa4O(BO3)(3) films grown on GdCa4O(BO3)(3) (0 1 0) substrates. (C) 2001 Elsevier Science B.V. All rights reserved.

  229. Magneto-optical properties of ZnO-based diluted magnetic semiconductors 査読有り

    K Ando, H Saito, ZW Jin, T Fukumura, M Kawasaki, Y Matsumoto, H Koinuma

    JOURNAL OF APPLIED PHYSICS 89 (11) 7284-7286 2001年6月

    出版者・発行元:AMER INST PHYSICS

    DOI: 10.1063/1.1356035  

    ISSN:0021-8979

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    Magnetic circular dichroism (MCD) spectra of Zn1-xTMxO (TM = Sc, Ti, V, Cr, Mn, Co, Ni, and Cu) films were measured to clarify their magneto-optical properties. Noticeable magneto-optical effect was not observed for Zn1-xScxO, Zn1-xTixO, Zn1-xVxO, and Zn1-xCrxO. On the contrary, Zn1-xMnxO, Zn1-xCoxO, Zn1-xNixO, and Zn1-xCuxO showed pronounced negative MCD peaks near 3.4 eV which correspond to the band gap of the host ZnO semiconductor. These results show that ZnO alloyed with Mn, Co, Ni, and Cu is a diluted magnetic semiconductor with strong exchange interaction between sp-band carriers and localized d electrons. (C) 2001 American Institute of Physics.

  230. High throughput fabrication of transition-metal-doped epitaxial ZnO thin films: A series of oxide-diluted magnetic semiconductors and their properties 査読有り

    ZW Jin, T Fukumura, M Kawasaki, K Ando, H Saito, T Sekiguchi, YZ Yoo, M Murakami, Y Matsumoto, T Hasegawa, H Koinuma

    APPLIED PHYSICS LETTERS 78 (24) 3824-3826 2001年6月

    出版者・発行元:AMER INST PHYSICS

    DOI: 10.1063/1.1377856  

    ISSN:0003-6951

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    Combinatorial laser molecular-beam epitaxy method was employed to fabricate epitaxial ZnO thin films doped with all the 3d transition metal (TM) ions in a high throughput fashion. The solubility behavior of TM ions was discussed from the viewpoints of the ionic radius and valence start. The magneto-optical responses coincident with absorption spectra were observed for Mn- and Co-doped samples. Cathodoluminescence spectra were studied for Cr-, Mn-, Fe-, and Co-doped samples. among which Cr-doped ZnO showed two sharp peaks at 2.97 eV and 3.71 eV, respectively, at the expense of the exciton emission peak of pure ZnO at 3.25 eV. Different magnetoresistance behavior was observed for the samples codoped with n-type carriers. Ferromagnetism was not observed for Cr- to Cu-doped samples down to 3 K. (C) 2001 American Institute of Physics.

  231. Anatase TiO2 thin films grown on lattice-matched LaAlO3 substrate by laser molecular-beam epitaxy 査読有り

    M Murakami, Y Matsumoto, K Nakajima, T Makino, Y Segawa, T Chikyow, P Ahmet, M Kawasaki, H Koinuma

    APPLIED PHYSICS LETTERS 78 (18) 2664-2666 2001年4月

    出版者・発行元:AMER INST PHYSICS

    DOI: 10.1063/1.1365412  

    ISSN:0003-6951

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    Epitaxial anatase thin films were fabricated on lattice-matched (-0.2%) LaAlO3 (001) substrates in the layer-by-layer fashion by laser molecular-beam epitaxy. X-ray diffraction and transmission electron microscope show the films to exhibit high crystallinity and atomically defined interfaces. By virtue of the adoption of LaAlO3 substrate, which is transparent to photoexcitation of TiO2, optical band gaps could be determined to be 3.3 eV at room temperature. A photoluminescence band due to recombination of self-trapped excitons was observed at 5 K to give the peak maximum at 2.2 eV. As a result of the high degree of orientation of the epitaxial films, anisotropic optical absorption was clearly observed. (C) 2001 American Institute of Physics.

  232. Large magneto-optical effect in an oxide diluted magnetic semiconductor Zn1-xCoxO 査読有り

    K Ando, H Saito, ZW Jin, T Fukumura, M Kawasaki, Y Matsumoto, H Koinuma

    APPLIED PHYSICS LETTERS 78 (18) 2700-2702 2001年4月

    出版者・発行元:AMER INST PHYSICS

    DOI: 10.1063/1.1368375  

    ISSN:0003-6951

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    Strong magneto-optical effect of Zn1-xCoxO near the optical band gap is reported. Magnetic circular dichroism (MCD) and Faraday rotation of Zn1-xCoxO (x=0.012 and 0.016) at 5 K are as high as 2 degrees /cm Oe at 3.4 eV, which are about two orders larger than those of ZnO. Absence of strong Co2+ d-d(*) transition near the optical band gap makes Zn1-xCoxO an useful material for short-wavelength magneto-optical applications. Large magneto-optical effects and paramagnetic temperature dependence of MCD show a strong mixing of the sp bands of the host ZnO with Co2+ d orbitals. The polarity of the MCD peak is negative indicating the antiferromagnetic p-d exchange interaction. (C) 2001 American Institute of Physics.

  233. Room-temperature ferromagnetism in transparent transition metal-doped titanium dioxide 査読有り

    Y Matsumoto, M Murakami, T Shono, T Hasegawa, T Fukumura, M Kawasaki, P Ahmet, T Chikyow, S Koshihara, H Koinuma

    SCIENCE 291 (5505) 854-856 2001年2月

    出版者・発行元:AMER ASSOC ADVANCEMENT SCIENCE

    DOI: 10.1126/science.1056186  

    ISSN:0036-8075

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    Dilute magnetic semiconductors and wide gap oxide semiconductors are appealing materials for magnetooptical devices, From a combinatorial screening approach looking at the solid solubility of transition metals in titanium dioxides and of their magnetic properties, we report on the observation of transparent ferromagnetism in cobalt-doped anatase thin films with the concentration of cobalt between 0 and 8%, Magnetic microscopy images reveal a magnetic domain structure in the films, indicating the existence of ferromagnetic long-range ordering, The materials remain ferromagnetic above room temperature with a magnetic moment of 0.32 Bohr magnetons per cobalt atom, The film is conductive and exhibits a positive magnetoresistance of 60% at 2 kelvin.

  234. Site-specific studies on X-ray magnetic circular dichroism at FeK edge for transition-metal ferrites 査読有り

    K Matsumoto, F Saito, T Toyoda, K Ohkubo, K Yamawaki, T Mori, K Hirano, M Tanaka, S Sasaki

    JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS 39 (10) 6089-6093 2000年10月

    出版者・発行元:JAPAN SOC APPLIED PHYSICS

    DOI: 10.1143/JJAP.39.6089  

    ISSN:0021-4922

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    Experiments on X-ray magnetic circular dichroism (XMCD) were performed with synchrotron radiation for Zn and Mn-Zn ferrites (normal-spinel structure) and Ni, Co and Cu ferrites and magnetite (inverse-spinel structure). The inverse-spinel ferrites have have positive-to-negative dispersion-type XMCD signals in the pre-edge region of the Fe K edge, which originate from Fe3+ ions in the A sites. There are no such signals for normal-spinel fel-rites. Two kinds of negative-to-positive dispersion-type XMCD signals were observed in 7.119-7.125keV and 7.122-7.129 keV regions of the main edge, which are caused by a mixture of Fe3+ and Fe2+ ions of the B sites in magnetite and Fe3+ ions of the B sites in the other inverse-spinel ferrites, respectively, The B-site origin of the XMCD main-edge spectra was also confirmed by observation of X-ray resonant magnetic scattering for the 222 reflection of Ni ferrite.

  235. Room-temperature stimulated emission of excitons in ZnO/(Mg, Zn)O superlattices 査読有り

    A Ohtomo, K Tamura, M Kawasaki, T Makino, Y Segawa, ZK Tang, GKL Wong, Y Matsumoto, H Koinuma

    APPLIED PHYSICS LETTERS 77 (14) 2204-2206 2000年10月

    出版者・発行元:AMER INST PHYSICS

    DOI: 10.1063/1.1315340  

    ISSN:0003-6951

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    We report on the observation of stimulated emission in ZnO/MgxZn1-xO superlattices well above room temperature. Two kinds of superlattices grown by laser molecular-beam epitaxy showed clear systematics on the quantum subband levels in absorption and spontaneous emission spectra. Stimulated emission with excitonic origin could be observed at very low optical pumping levels. The threshold excitation intensity changed from 11 to 40 kW/cm(2), and the emission energy could be tuned between 3.2 and 3.4 eV, depending on the well thickness and/or the Mg content in the barrier layers. The excitonic stimulated emission could be observed up to 373 K and the characteristic temperature was as high as 87 K. (C) 2000 American Institute of Physics. [S0003- 6951(00)04640-4].

  236. Investigation of ZnO/sapphire interface and formation of ZnO nanocrystalline by laser MBE 査読有り

    Ohkubo, I, Y Matsumoto, A Ohtomo, T Ohnishi, A Tsukazaki, M Lippmaa, H Koinuma, M Kawasaki

    APPLIED SURFACE SCIENCE 159 514-519 2000年6月

    出版者・発行元:ELSEVIER SCIENCE BV

    DOI: 10.1016/S0169-4332(00)00138-0  

    ISSN:0169-4332

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    Epitaxial ZnO thin films were prepared on atomically flat sapphire (alpha-Al2O3) (0001) substrates at various substrate temperatures by laser molecular beam epitaxy. Crystal structure was analyzed by four-circle X-ray diffraction. Atomic force microscope (AFM) and reflection high energy electron diffraction (RHEED) were used to evaluate surface morphology. When ZnO was deposited on atomically flat sapphire (0001), an epitaxial ZnO film was grown with c-axis orientation, having two different in-plane orientation, ZnO [1010] \\ sapphire [1010] (400-450 degrees C) and ZnO [1010] \\ sapphire [1120] (800-835 degrees C), depending on deposition temperature. The detailed observation of the initial growth of ZnO film deposited at 835 degrees C revealed that the growth mode followed Stranski-Krastanov growth mechanism. (C) 2000 Elsevier Science B.V. All rights reserved.

  237. Combinatorial laser MBE synthesis of 3d ion doped epitaxial ZnO thin films 査読有り

    ZW Jin, M Murakami, T Fukumura, Y Matsumoto, A Ohtomo, M Kawasaki, H Koinuma

    JOURNAL OF CRYSTAL GROWTH 214 55-58 2000年6月

    出版者・発行元:ELSEVIER SCIENCE BV

    DOI: 10.1016/S0022-0248(00)00058-0  

    ISSN:0022-0248

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    Combinatorial laser MBE (CLMBE) method was employed to fabricate epitaxial ZnO thin films doped with all the 3d transition metal ions, The solubility behavior of 3d ions was studied from the viewpoints of ionic radius and valence state. Transmission spectra were classified into four groups with respect to the absorption edge shifts and d-d electron transitions. Mn2+ and Co2+ ions show very high solubility limits among all the 3d ion species and have high spin electron configurations in ZaO matrix. Such a high throughput synthesis tool as CLMBE is shown to be a powerful tool for exploring novel functionality of thin film materials. (C) 2000 Elsevier Science B.V. All rights reserved.

  238. Concept and development of combinatorial laser MBE for oxide electronics 査読有り

    H Koinuma, M Kawasaki, T Itoh, A Ohtomo, M Murakami, ZW Jin, Y Matsumoto

    PHYSICA C 335 (1-4) 245-250 2000年6月

    出版者・発行元:ELSEVIER SCIENCE BV

    DOI: 10.1016/S0921-4534(00)00178-7  

    ISSN:0921-4534

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    As a treasure island of new functional materials, metal oxides attract rapidly growing interest as exemplified by the high-T-c cuprates and quantum. functional perovskites. The development of new efficient instrument to construct artificially designed crystal lattices and hetro-junctions is considered to facilitate the systematic exploration of new materials, properties, and application of oxides. Powerful tools for this purpose are designed based on combinatorial chemistry and molecular layer epitaxy. With focuses on the concept and method, this novel technology of combinatorial laser MBE is reported and demonstrated to be useful for high throughput synthesis of functional oxide thin films and layered lattices. (C) 2000 Published by Elsevier Science B.V.

  239. Self-organized structure in Co thin film growth on c(2 x 2)-N-Cu(100) surfaces 査読有り

    K Mukai, Y Matsumoto, K Tanaka, F Komori

    SURFACE SCIENCE 450 (1-2) 44-50 2000年4月

    出版者・発行元:ELSEVIER SCIENCE BV

    DOI: 10.1016/S0039-6028(99)01245-5  

    ISSN:0039-6028

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    Thin film growth of Co at room temperature is studied by scanning tunneling microscopy on a surface consisting of regularly arranged c(2 x 2)-N-Cu(100) square patches separated by a narrow and clean Cu surface. One monolayer ( ML) thick Co grows selectively on the bare Cu surface in the early stage of Co deposition on the surface, and there forms a square lattice made of 1 ML thick Co wires on Cu. With increasing amount of Co deposition, 2 and 3 ML thick Co islands grow selectively at the intersection of the wires. Consequently, square arrays of Co small islands are formed that are interconnected by Co narrow wires. These are compared with Ni growth on the same surface, and discussion is made in terms of diffusion, sticking and crystal structures of the deposited metals on the surface. (C) 2000 Published by Elsevier Science B.V. All rights reserved.

  240. Can ZnO Eat Market in Optoelectronic Applications? 査読有り

    M. Kawasaki, K. Tamura, K. Saikusa, T. Aita, A. Tsukazaki, A. Ohtomo, Z. Jin, Y. Matsumoto, T. Fukumura, H. Koinuma

    Solid State Devices and Materials 2000 128-129 2000年

  241. In-plane and polar orientations of ZnO thin films grown on atomically flat sapphire 査読有り

    Ohkubo, I, A Ohtomo, T Ohnishi, Y Mastumoto, H Koinuma, M Kawasaki

    SURFACE SCIENCE 443 (1-2) L1043-L1048 1999年12月

    出版者・発行元:ELSEVIER SCIENCE BV

    DOI: 10.1016/S0039-6028(99)01024-9  

    ISSN:0039-6028

    詳細を見る 詳細を閉じる

    Epitaxial ZnO thin films were prepared on atomically flat sapphire (0001) substrates at various temperatures by laser molecular beam epitaxy. On the as-polished substrates, the in-plane orientation of ZnO thin films was found to be ZnO [10 (1) over bar 0]parallel to sapphire [11 (2) over bar 0] regardless of the deposition conditions. However, films on atomically flat substrates showed two in-plane orientations, ZnO [10 (1) over bar 0]parallel to sapphire [10 (1) over bar 0] and ZnO [10 (1) over bar 0]parallel to sapphire [11 (2) over bar 0], rotated by 30 degrees for films grown at low (400-450 degrees C) and high (800-835 degrees C) temperatures respectively. Ion scattering spectroscopy revealed that the former films were (0001) oriented with the Zn-face forming the topmost surface, whereas the latter films had the (000 (1) over bar) orientation with the O-face at the film surface. This orientation change is discussed by taking thermodynamic stability and growth kinetics into account. The films grown at very high temperature (835 degrees C) showed superior crystallinity even in comparison with bulk single crystals. (C) 1999 Elsevier Science B.V. All rights reserved.

  242. Combinatorial laser molecular beam epitaxy (MBE) growth of Mg-Zn-O alloy for band gap engineering 査読有り

    Y Matsumoto, M Murakami, ZW Jin, A Ohtomo, M Lippmaa, M Kawasaki, H Koinuma

    JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS 38 (6AB) L603-L605 1999年6月

    出版者・発行元:JAPAN J APPLIED PHYSICS

    DOI: 10.1143/jjap.38.L603  

    ISSN:0021-4922

    詳細を見る 詳細を閉じる

    We have developed a new combinatorial synthesis system integrating a combinatorial shadow mask into a laser MBE (molecular beam epitaxy) chamber. This combinatorial Laser MBE system can be used for fabricating a number of crystalline films with different compositions on a substrate under programmed temperature and pressure conditions. The method was applied to alloying and band gap engineering of ZnO by positional substitution of ME into ZnO thin films. The superiority of the combinatorial methodology to conventional one-by-one synthesis is evident from the high linearity of the c-axis length and band gap dependence on Mg content.

  243. Spatial distribution of N-2, O-2 and NO molecules desorbing from a [p(2x1)-O+p(2x3)-N]Ag(110) surface 査読有り

    K Moriwaki, Y Matsumoto, M Ikai, K Tanaka

    CHEMICAL PHYSICS LETTERS 292 (4-6) 500-506 1998年8月

    出版者・発行元:ELSEVIER SCIENCE BV

    DOI: 10.1016/S0009-2614(98)00723-4  

    ISSN:0009-2614

    詳細を見る 詳細を閉じる

    Temperature-programmed desorption of a [p(2 X 3)-N + p(2 X I)-O]Ag(110) surface gives simultaneous desorption of N-2 and NO at 520 K and the desorption of O-2 at 600 K. The STM image showed a competitive array of (Ag4N) rows and (-Ag-O-) strings. N2 is formed by self-recombination of N-atoms, and NO is formed by the reaction of N-atoms with (-Ag-O-) strings. The spatial distribution of NO (520 K) took two maxima, in the normal and ca. 17 degrees off-normal directions, although N-2 and O-2 desorb only in the normal direction. These two maxima may reflect the reaction of N-atoms with O-atoms at the terminal and inside of the (-Ag-O-) strings. (C) 1998 Elsevier Science B.V. All rights reserved.

  244. Nano-scale patterning of metal surfaces by adsorption and reaction 査読有り

    K Tanaka, Y Matsumoto, T Fujita, Y Okawa

    APPLIED SURFACE SCIENCE 130 475-483 1998年6月

    出版者・発行元:ELSEVIER SCIENCE BV

    DOI: 10.1016/S0169-4332(98)00104-4  

    ISSN:0169-4332

    詳細を見る 詳細を閉じる

    Nano-scale patterning of the metal surfaces was attained by the adsorption and the reaction of metal atoms. Growth of metal islands on the metal surfaces was markedly influenced by preparing the surface with preadsorption and/or by the reconstruction. Adsorption of oxygen on Cu(100) form randomly coalesced nano-size c(2 x 2)-O which undergoes the (2 root 2 x root 2)R45 degrees reconstruction with increasing the oxygen coverage. In contrast, N-atoms on Cu(100) make well ordered array of squared c(2 x 2)-N patches of ca. 50 Angstrom(2). Cu atoms deposited on the nano-size c(2 x 2)-O Cu(100) form one atomic height rectangular Cu islands but Ni atoms undergo no orientational growth of Ni islands. Ni atoms deposited on the (2 root 2 x root 2)R45 degrees-O Cu(100) surface, however, gave an extremely anisotropic growth of Ni-wire. In contrast, when Ni atom was deposited on a Cu(100) surface having a super-grid like pattern made by the boundaries of squared c(2 x 2)-N patches, one atomic height Ni islands grew at the crossings of the super-grid. These phenomena are distinctive from the chemical reaction of surface atoms which provides various quasi-compounds. The reaction of Cu with (-Ag-O-) strings on Ag(110) provided a new quasi-compound of (-Cu-O-) on Ag(110), which undergoes a reversible reaction of (-Cu-O-) reversible arrow (Cu)(6) + O(2). In addition, the (-Ag-O-) strings on Ag(110) undergo selective photo-erasing These results suggest that chemical reaction is a promising tool for making atomic-scale pattern on the surface. (C) 1998 Elsevier Science B.V. All rights reserved.

  245. Growth of nanosize Ni thin films on a modified c(2x2)-n Cu(100) surface 査読有り

    Y Matsumoto, K Tanaka

    JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS & EXPRESS LETTERS 37 (2A) L154-L157 1998年2月

    出版者・発行元:JAPAN SOC APPLIED PHYSICS

    DOI: 10.1143/jjap.37.L154  

    ISSN:0021-4922

    詳細を見る 詳細を閉じる

    Growth of Ni on a c(2 x 2)-N Cu(100) surface was studied by scanning tunneling microscopy (STM). When Ni atoms are vaporized on a Cu(100) surface with square c(2 x 2)-N patches, one-atomic-layer Ni islands with an average size of 50 Angstrom are grown on the virgin area remaining at the corner of c(2 x 2)-N patches, so that uniform size Ni islands are arranged like a checkerboard, This checkerboard arrangement of Ni islands is stable up to 470 K. Stronger interaction of the Ni layer with the dean area compared to the c(2 x 2)-N area brings about this unique growth of Ni islands on the c(2 x 2)-N Cu(100) surface.

  246. An efficient way of doping experiments : Combinatorial laser MBE synthesis of epitaxial ZnO thin film doped with Sc, Ti, V, Cr, Mn, Fe, Co, Ni, and Cu

    Z. Jin, T. Fukumura, M. Murakami, Y. Matsumoto, A. Ohtomo, M. Kawasaki, H. Koinuma

    Extended Abstracts of the 5th Symposium on the Physics and Application of Spin-related Phenomena in Semiconductors 46-49 1998年

  247. Two kinds of adsorbed N atoms with different reactivities with H-2 on a Pt0.25Rh0.75(100) surface 査読有り

    K Moriwaki, Y Matsumoto, DL Lu, K Tanaka

    CATALYSIS LETTERS 52 (3-4) 151-155 1998年

    出版者・発行元:BALTZER SCI PUBL BV

    DOI: 10.1023/A:1019000326574  

    ISSN:1011-372X

    詳細を見る 詳細を閉じる

    Two kinds of adsorbed N atoms exist on a Pt0.25Rh0.75(100) surface. One desorbs at 490 K and the other desorbs at 650 K. The former reacts with H-2 at 400 K, but the latter does not. It is supposed that the adsorption of these two N atoms is responsible of the surface composition, ratio of Pt and Ph.

  248. STM observation of restructured Cu(001) surfaces induced by Li deposition 査読有り

    S Mizuno, H Tochihara, Y Matsumoto, K Tanaka

    SURFACE SCIENCE 393 (1-3) L69-L76 1997年12月

    出版者・発行元:ELSEVIER SCIENCE BV

    DOI: 10.1016/S0039-6028(97)00646-8  

    ISSN:0039-6028

    詳細を見る 詳細を閉じる

    We have studied the (2 x 1), (3 x 3) and (4 x 4) structures formed on Cu(001) with increasing Li coverage at 300 K using scanning tunneling microscope (STM). The STM images of the three phases support the previously determined structures by low-energy electron diffraction analysis. Details of the STM images of the (4 x 4) structure are discussed on the basis of the determined structure. A cluster of four Li adatoms on a small island of nine Cu atoms is observed as a single protrusion and the protrusions form the (4 x 4) lattice. We found migration of vacancies and domain boundaries. On the whole, however, the (4 x 4) structure is stable at 300 K on terraces. (C) 1997 Elsevier Science B.V.

  249. The growth mechanism of (-Cu-O-) strings on a Ag(110) surface studied by scanning tunneling microscopy, x-ray photoelectron spectroscopy, and high resolution electron energy loss spectroscopy 査読有り

    Y Matsumoto, K Sakamoto, Y Okawa, S Suto, K Tanaka

    JOURNAL OF CHEMICAL PHYSICS 107 (23) 10185-10190 1997年12月

    出版者・発行元:AMER INST PHYSICS

    DOI: 10.1063/1.474154  

    ISSN:0021-9606

    詳細を見る 詳細を閉じる

    A (-Cu-O-) string on a Ag(110) surface defined by scanning tunneling microscopy (STM) was studied using the x-ray photoelectron spectroscopy (XPS), high resolution electron energy loss spectroscopy (HREELS). These data give the information about bonding properties which cannot be derived from the STM images. The combinative studies could show the structure as well as the growth mechanism of (-Cu-O-) strings on the Ag(110) surface. Deposition of Cu atoms on a p(2 X 1)-O Ag(110) surface resulted in a new O(1s) peak at 529.9 eV in the XPS and a new electron energy loss peak at 35 meV in the HREELS. These new peaks are assignable to the (Cu-O) bonding state on Ag(110), which is corresponding to the growth of new (-Cu-O-) strings in the [&lt;1(1)over bar&gt;0] direction shown by the STM. These results suggest a stoichiometric reaction producing (-Cu-O-) strings according to an equation of (-Ag-O-)+Cu--&gt;(-Cu-O-)+Ag on the Ag(110) surface, The fact that the Ag atoms released by the chemical reaction make layered Ag islands and the (-Cu-O-) strings also grow on the Ag islands in the [1 (1) over bar 0] direction is indicative that the reaction proceeds perfectly in stoichiometric manner over the terrace. (C) 1997 American Institute of Physics. [S0021-9606(97)03047-X].

  250. STM studies of oxygen-induced reconstruction on a Pt-Rh(100) alloy surface 査読有り

    Y Matsumoto, Y Aibara, K Mukai, K Moriwaki, Y Okawa, BE Nieuwenhuys, K Tanaka

    SURFACE SCIENCE 377 (1-3) 32-37 1997年4月

    出版者・発行元:ELSEVIER SCIENCE BV

    DOI: 10.1016/S0039-6028(96)01323-4  

    ISSN:0039-6028

    詳細を見る 詳細を閉じる

    Oxygen-induced reconstruction of a Pt-Rh(100) alloy surface was studied by scanning tunneling microscopy (STM). When a clean Pt-enriched Pt-Rh(100) surface was exposed to O-2 at more than 600 K, oxygen-induced reconstruction took place with segregation of Rh atoms to the surface. Depending on the coverage of oxygen, two types of reconstruction on the Pt-Rh(100) alloy surface are induced. A p(3 x 1)-O structure appeared at relatively low oxygen coverage, and the TPD spectrum of the p(3 x 1)-O surface gave a desorption peak of O-2 at ca. 930 K. The p(3 x 1)-O structure showed several different STM images depending on the tip condition, from which we could distinguish the two component metals, Rh-O rows and Pt rows. Based on this, a model structure was deduced. At a high oxygen coverage, more Rh atoms were segregated to the surface and the STM image suggests a c(2 x 20)-O structure. The c(2 x 20)-O surface changed into the p(3 x 1)-O by heating with the concomitant desorption of O-2 at ca. 830 K. The STM images for this c(2 x 20)-O surface is analogous to the arrangement of Ph atoms on the top layer of a Rh(lll) hexagonal lattice. Due to the lattice mismatch between the quasi-Rh(lll) overlayer and Pt-Rh(100) substrate, a moire pattern with 20 times periodicity along the [011] directions was observed. Both the p(3 x 1)-O and c(2 x 20)-O surfaces are easily reduced by H-2 even at room temperature.

  251. Atomic-scale fabrication of novel surfaces using chemical reactions 査読有り

    K Tanaka, Y Okawa, Y Matsumoto, T Fujita

    SURFACE SCIENCE 377 (1-3) 744-753 1997年4月

    出版者・発行元:ELSEVIER SCIENCE BV

    DOI: 10.1016/S0039-6028(96)01493-8  

    ISSN:0039-6028

    詳細を見る 詳細を閉じる

    An idea of the chemical reconstruction caused by the formation of quasi-compounds and their self-assembly is defined. New surfaces were fabricated by combining the reaction of the quasi-compounds and their self-assembly, a quasi-compound of (-Cu-O-) strings was grown in the [1(1) over bar0$] direction on Ag(110) by the reaction of (-Ag-O-) strings with Cu atoms, which brought about a reversible reaction of (-Cu-O-)reversible arrow(Cu)(6) + O-2. By the reaction of (-Ag-O-) strings with CO2, a composite structure of (-Ag-O-) and (AgCO3) was established on the Ag(110) surface. When Cu atoms were vaporized on this composite surface, the (-Ag-O-) strings reacted selectively with Cu atoms, and (-Cu-O-) strings grew in the [110] direction, Interestingly, an opposite selective reaction occurred when the composite surface was scanned with a W tip coated with Ct; that is, Ct atoms react selectively with carbonate species. These phenomena suggest that the chemical reaction and the chemical transportation reaction will make realize atomic scale surface fabrication possible. The photochemical reaction of a quasi-compound was also attained on a composite surface of (-Ag-O-) and (Ag2N) strings on the Ag(110) surface, where the (Ag-O-) strings were selectively erased by illumination.

  252. Acquisition of translation rules from parallel corpora 査読有り

    Y Matsumoto, M Kitamura

    RECENT ADVANCES IN NATURAL LANGUAGE PROCESSING 136 405-416 1997年

    出版者・発行元:JOHN BENJAMINS B V PUBL

    ISSN:0304-0763

    詳細を見る 詳細を閉じる

    This article presents a method of automatic acquisition of translation rules from a bilingual corpus. Translation rules are extracted by the results of structural matching of parallel sentences. The structural matching process is controlled by the word similarity dictionary, which is also obtained from the parallel corpus. The system acquires translation equivalences of word-level as well as those of multiple word or phrase-level.

  253. Selective photobleaching of (-Ag-O-) strings on the Ag(110) surface 査読有り

    Y Matsumoto, Y Okawa, K Suzuki, K Mukai, K Tanaka

    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 118 (40) 9676-9679 1996年10月

    出版者・発行元:AMER CHEMICAL SOC

    DOI: 10.1021/ja9614070  

    ISSN:0002-7863

    詳細を見る 詳細を閉じる

    A p(2x3)-N Ag(110) surface obtained by N+ and/or N-2(+) ion bombardment gave a desorption peak of N-2 at 530 K. When this p(2x3)-N Ag(110) surface was exposed to O-2 at room temperature, the LEED pattern showed a combined structure of [p(2x3)-N + p(2x1)-O]. The STM image proved the growth of the (-Ag-O-) and (Ag2N) strings in the [001] and [1(1) over bar0$] directions, respectively. The TPD spectrum of the combined surface gave the desorption of N-2 at 530 K, NO at 490-520 K, and O-2 at 600 K. When this [p(2x3)-N + p(2x1)-O] Ag(110) surface was illuminated with a UV light at room temperature, the (-Ag-O-) strings in the STM image were selectively erased although the (Ag2N) underwent little influence, and the LEED pattern changed to the p(2x3)-N structure, The TPD spectrum of the surface after the illumination gave only N-2. These results indicate that surface migration of N atoms triggers the reaction between N and N yielding N-2 as well as N and O yielding NO on the surface. Selective photobleaching for the combined structure may suggest a feasibility of atomic scale lithography of the surface by using photochemical reactions.

  254. Phase boundaries of nanometer scale c(2x2)-O domains on the Cu(100) surface 査読有り

    T Fujita, Y Okawa, Y Matsumoto, K Tanaka

    PHYSICAL REVIEW B 54 (3) 2167-2174 1996年7月

    出版者・発行元:AMERICAN PHYSICAL SOC

    DOI: 10.1103/PhysRevB.54.2167  

    ISSN:1098-0121

    詳細を見る 詳細を閉じる

    A scanning tunneling microscope (STM) showed the formation of nanometer size c(2x2) domains of adsorbed oxygen on the Cu(100) surface when oxygen coverage is low, though large well-ordered c(2x2) domains were not observed. The STM image of the phase boundaries of these nanometer size c(2x2)-O domains showed complex zigzag bright lines surrounding the c(2x2) domains, and the low-energy electron diffraction pattern of this surface gave a ''four-spot'' pattern, which can be explained by a local c(2x2) domain model.

  255. STM studies of a catalytically active p(3x1) Pt-Rh(100) alloy surface 査読有り

    Y Matsumoto, Y Okawa, T Fujita, K Tanaka

    SURFACE SCIENCE 355 (1-3) 109-114 1996年6月

    出版者・発行元:ELSEVIER SCIENCE BV

    DOI: 10.1016/0039-6028(96)01359-3  

    ISSN:0039-6028

    詳細を見る 詳細を閉じる

    Oxygen-induced p(3 x 1) reconstruction of a Pt0.25Rh0.75(100) alloy surface was studied by scanning tunneling microscopy (STM). When a Pt-enriched (1 x 1) Pt-Rh(100) alloy surface was exposed to O-2, a clear p(3 x 1) LEED pattern appeared at temperatures higher than ca. 400 K, and segregation of Rh atoms was observed by STM. Once the p(3 x 1) Pt-Rh(100) surface is established at T greater than or equal to 400 K, a reversible interconversion, p(3 x 1)--&gt;p(1 x 1) by H-2 and p(1 x 1)--&gt;p(3 x 1) by O-2, is brought about at room temperature. The p(3 x 1) surface showed three different STM images, depending on the tip condition, from which a model structure was deduced. The first formation of the p(3 x 1) structure requires the segregation of Rh atoms, but the interconversion between the p(3 x 1) and p(1 x 1) structures is responsible for the oxygen-induced array of Rh atoms along the [011]directions.

  256. A reversible reaction forming (-Cu-O-) strings and (Cu)(6)-clusters on Ag(110) shown by STM 査読有り

    Y Matsumoto, K Tanaka

    SURFACE SCIENCE 350 (1-3) L227-L231 1996年4月

    出版者・発行元:ELSEVIER SCIENCE BV

    DOI: 10.1016/0039-6028(95)01341-5  

    ISSN:0039-6028

    詳細を見る 詳細を閉じる

    An artificial new surface of (-Cu-O-) chains grown on Ag(110) surface was prepared by reacting a p(2 x 1)Ag-O/Ag(110) surface with Cu atoms, where the (-Cu-O-) chains grow in the [1(1) over bar0$] direction and are self-assembled on the Ag(110) surface in a (2 x 2)-p2mg structure. When the Cu-O/Ag(110) surface was heated in vacuum, the (-Cu-O-) chain decomposed to uniform size Cu-atom cluster dots arranged along the [1(1) over bar0$] direction, where the cluster dots were composed of six Cu atoms. When the Ag(110) surface with the Cu-duster dots was exposed to O-2, the (-Cu-O-) lines were redrawn along the [1(1) over bar0$] direction by reacting a series of dots in the [1(1) over bar0$] direction with O-2. This is a reversible chemical reaction in one dimensional regime proved in atomic resolution.

  257. Atomic scale reaction regulated in one-dimensional channels evidenced by scanning tunneling microscopy 査読有り

    Y Matsumoto, K Tanaka

    JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B 14 (2) 1114-1116 1996年3月

    出版者・発行元:AMER INST PHYSICS

    DOI: 10.1116/1.588410  

    ISSN:1071-1023

    詳細を見る 詳細を閉じる

    By reacting (-Ag-O-) strings on Ag(110) with Cu atoms at room temperature, (-Cu-O-) strings were grown on the Ag(110) surface. The (-Cu-O-) chains grow along the [110] direction and are ordered in a p2mg(2x2) structure on the Ag(110) surface. When a p2mg(2x2)(-Cu-O-)/Ag(110) surface was heated for several minutes at 570 g, the (-Cu-O-) strings were rearranged to a p(1x3) structure and the (-Cu-O-) strings underwent the preferential decomposition along the phase boundary of the p(1x3) domains. The decomposition of the (-Cu-O-) strings yielded uniform size (Cu)(6) cluster dots (similar to 8 A) along the [1(1) over bar 0] axis on the Ag(110) surface and its reverse reaction, the (Cu)(6)+O-2--&gt;(-Cu-O-) string, took place also along the [1(1) over bar 0] axis at room temperature. (C) 1996 American Vacuum Society.

  258. Structure of the p(2X3) Ni(110)-N surface studied by scanning tunneling microscopy 査読有り

    N Takehiro, Y Matsumoto, Y Okawa, K Tanaka

    PHYSICAL REVIEW B 53 (7) 4094-4098 1996年2月

    出版者・発行元:AMERICAN PHYSICAL SOC

    DOI: 10.1103/PhysRevB.53.4094  

    ISSN:0163-1829

    詳細を見る 詳細を閉じる

    A p(2x3) Ni(110)-N surface was studied by scanning tunneling microscopy. A coupled string overlays on the three Ni rows in the [1(1) over bar0$] direction on the Ni(110) surface, and the line is resolved in atomic periodicity of 2.5 Angstrom distance along the [1(1) over bar0$] direction. These atomic structures correspond to the p(2X3) Ni(110)-N surface. The sites for N and/or Ni atoms were deduced by using a guide of the (-Ni-O-) chains on the Ni(110) surface. which suggests that the N atoms are on the threefold sites with two Ni atoms and one subsurface Ni atom. When a p(2X3) Ni(110)-N surface is exposed to H atoms, a bright dumbbell-shape pattern appeared at the terminal edge of the (Ni-N) domains, which may correspond to the formation of NH species, Based on these results, a structure model was proposed, which model is in good agreement with the experimental results of surface-extended x-ray-absorption fine structure and low-energy impact-collision ion-scattering spectroscopy.

  259. Growth and ordering of Cu-O chains on Ag(110) surface (vol 336, pg L762, 1995) 査読有り

    Y Matsumoto, Y Okawa, K Tanaka

    SURFACE SCIENCE 344 (1-2) 183-183 1995年12月

    出版者・発行元:ELSEVIER SCIENCE BV

    DOI: 10.1016/0039-6028(95)00947-7  

    ISSN:0039-6028

  260. GROWTH AND ORDERING OF CU-O CHAINS ON AG(110) SURFACE 査読有り

    Y MATSUMOTO, Y OKAWA, K TANAKA

    SURFACE SCIENCE 336 (3) L762-L766 1995年8月

    出版者・発行元:ELSEVIER SCIENCE BV

    DOI: 10.1016/0039-6028(95)00642-7  

    ISSN:0039-6028

    詳細を見る 詳細を閉じる

    Growth of Cu-O chains and their ordering on Ag(110) surface were monitored by scanning tunneling microscopy (STM). When Cu atoms were deposited on a (2 X 1) Ag-O/Ag(110) surface at room temperature, the Ag-O chains in the [001] direction diminished and new strings of Cu-O grew along the [110] direction and yield a (2 X 2) p2mg ordering. When a Ag(110) surface with coexisting Ag-O and Cu-O chains was exposed to CO at room temperature, the Ag-O chains were selectively reduced.

  261. GROWTH OF CU-O CHAINS ON AG(110) SURFACES 査読有り

    Y MATSUMOTO, Y OKAWA, K TANAKA

    SURFACE SCIENCE 325 (3) L435-L440 1995年3月

    出版者・発行元:ELSEVIER SCIENCE BV

    DOI: 10.1016/0039-6028(94)00838-8  

    ISSN:0039-6028

    詳細を見る 詳細を閉じる

    The (Ag-O) chains grown along the [001] direction on Ag(110) disappeared by the reaction with Cu atoms at room temperature, and new one-dimensional chains grew in the [110] direction. The STM images at different bias potentials suggest the growth of (Cu-O) chains in the [110] direction on the Ag(110) surface. The (Cu-O) chains on the Ag(110) surface disappeared by heating to 470 K, but they reappeared by exposing to O-2 at room temperature.

  262. A NEW PREPARATION METHOD OF LAMNO3 PEROVSKITE FILM ON SRTIO3 ELECTRODE 査読有り

    Y MATSUMOTO, T SASAKI, J HOMBO

    JOURNAL OF THE ELECTROCHEMICAL SOCIETY 138 (5) 1259-1263 1991年5月

    出版者・発行元:ELECTROCHEMICAL SOC INC

    DOI: 10.1149/1.2085769  

    ISSN:0013-4651

    詳細を見る 詳細を閉じる

    Photoelectrochemical deposition of the LaMnO3 precursor was investigated on SrTiO3 and TiO2 single-crystal semi-conductor electrodes [(100) plane] in solutions containing Mn2+ and La3+ ions. Deposition of the LaMnO3 precursor was always observed on the SrTiO3 electrode, but not on the TiO2 electrode. Pre-electrolysis of the TiO2 electrode in solutions containing La3+ ion was necessary for the LaMnO3 precursor deposition. Thus, the LaMnO3 precursor deposition needs perovskite or perovskite-like conditions at the electrode surface. Only anodic photocurrent contributes to the LaMnO3 precursor deposition, but tunneling current does not. This suggests that OH radical produced by the photo-process is also important for the formation of the LaMnO3 precursor on the electrode. It was presumed that the LaMnO3 precursor is an amorphous LaMnO3-delta. The LaMnO3 perovskite film with a-axial orientation was formed on SrTiO3 by the heat-treatment at temperature higher than 600-degrees-C. Thus, a possibility of the epitaxial growth of LaMnO3 perovskite on SrTiO3 single-crystal electrode is demonstrated in this paper.

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    丸山伸伍, 高川佑輔, 小金澤智之, 松本祐司

    応用物理学会春季学術講演会講演予稿集(CD-ROM) 66th 2019年

  6. イオン液晶上におけるペンタセン薄膜成長

    田中深雪, 丸山伸伍, 小金澤智之, 松本祐司

    応用物理学会秋季学術講演会講演予稿集(CD-ROM) 80th 2019年

  7. 真空蒸着PTCDI-C8薄膜における巨大グレイン成長のその場GIXD測定

    高川佑輔, 丸山伸伍, 小金澤智之, 宮寺哲彦, 松本祐司

    応用物理学会秋季学術講演会講演予稿集(CD-ROM) 80th 2019年

  8. Si-Agフラックスを用いたSiC結晶化過程のin situ XRD観察

    山王堂尚輝, 丸山伸伍, 小金澤智之, 松本祐司

    応用物理学会秋季学術講演会講演予稿集(CD-ROM) 80th 2019年

  9. ペリレン誘導体蒸着膜における巨大なグレイン成長

    丸山伸伍, 高川佑輔, 松本祐司, 小金澤智之

    日本表面真空学会東北・北海道支部学術講演会講演予稿集 2018 2019年

  10. イオン液体の真空化学プロセス 招待有り

    丸山伸伍, 松本祐司

    化学工業 69 (10) 41-50 2018年10月

  11. 傾斜組成Bi<sub>1-x</sub>Sm<sub>x</sub>FeO<sub>3</sub>薄膜の分極反転挙動

    穴田柚冬, 丸山伸伍, 安井伸太郎, 永沼博, 伊藤満, 松本祐司

    応用物理学会秋季学術講演会講演予稿集(CD-ROM) 79th 2018年

    ISSN:2758-4704

  12. 真空蒸着PTCDI-C8薄膜における巨大グレイン成長

    高川佑輔, 丸山伸伍, 小金澤智之, 松本祐司

    応用物理学会秋季学術講演会講演予稿集(CD-ROM) 79th 2018年

  13. イオン液体を用いた真空材料プロセス 招待有り

    松本祐司, 丸山伸伍

    THE CHEMICAL TIMES 246 (4) 14-19 2017年

  14. Fe<sub>3</sub>O<sub>4</sub>薄膜のSolid-state dewettingのAFM観察

    正能大起, 高橋竜太, 小沼碧海, 丸山伸伍, 松本祐司, JAHANGIR Solmaz, NAGARAJAN Valanoor, LIPPMAA Mikk

    応用物理学会春季学術講演会講演予稿集(CD-ROM) 63rd 2016年

  15. Fe<sub>3</sub>O<sub>4</sub>薄膜のDewetting現象の基板依存性

    正能大起, 高橋竜太, 小沼碧海, 丸山伸伍, 松本祐司, JAHANGIR Solmaz, NAGARAJAN Valanoor, LIPPMAA Mikk

    応用物理学会秋季学術講演会講演予稿集(CD-ROM) 76th 2015年

  16. Fe<sub>3</sub>O<sub>4</sub>薄膜のDewettingプロセスの観察

    正能大起, 高橋竜太, 小沼碧海, 丸山伸伍, 松本祐司, JAHANGIR Solmaz, NAGARAJAN Valanoor, LIPPMAA Mikk

    応用物理学会春季学術講演会講演予稿集(CD-ROM) 62nd 2015年

  17. イオン液体ゲートを用いたLiTi<sub>2</sub>O<sub>4</sub>薄膜の超伝導転移温度の変調

    丸山伸伍, 丸山伸伍, SHIN Jongmoon, ZHANG Xiaohang, KUI Jin, SUCHOSKI Richard, 安井伸太郎, 安井伸太郎, 松本祐司, GREENE Richard L., 竹内一郎

    応用物理学会春季学術講演会講演予稿集(CD-ROM) 61st 2014年

    ISSN:2436-7613

  18. 27aEB-6 ThRu_2Si_2のde Haas-van Alphen効果測定によるフェルミ面の研究(アクチナイド(URu_2Si_2の隠れた秩序・遍歴強磁性・超伝導),領域8(強相関系分野:高温超伝導,強相関f電子系など))

    松本 祐司, 芳賀 芳範, 立岩 尚之, 青木 晴善, 木村 憲彰, 山本 悦嗣, Fisk Zachary, 山上 浩志

    日本物理学会講演概要集 68 (2) 553-553 2013年8月26日

    出版者・発行元:一般社団法人日本物理学会

    ISSN:1342-8349

  19. イオン液体を介した真空蒸着法による薄膜形成技術の開発 招待有り 査読有り

    武山洋子, 丸山伸伍, 松本祐司

    表面科学 34 (4) 198-203 2013年

    出版者・発行元:The Surface Science Society of Japan

    DOI: 10.1380/jsssj.34.198  

    ISSN:0388-5321

    詳細を見る 詳細を閉じる

    Ionic liquid has attracted much attention as a stable liquid even in vacuum, which feature has allowed us to propose a new application of the ionic liquid used as a crystallization solvent in a vacuum deposition process. In this review, we introduce a good example of the successful application to the vacuum deposition of single crystals and films of pentacene in ionic liquid. In this ionic liquid-assisted vacuum deposition, the pentacene is found to grow almost under the thermodynamic equilibrium condition with an aid of the ionic liquid, being of very high-quality in crystallinity as compared to those obtained by the simple vacuum deposition process without ionic liquid. The effects of not only the kind, but also the size and shape of the ionic liquids as the solvent on the initial nucleation and the subsequent growth of the pentacene crystal are discussed.

  20. 光触媒作用はなぜ再現しないことが多いのか?

    松本祐司

    表面科学 34 (7) 368-373 2013年

    出版者・発行元:Surface Science Society Japan

    DOI: 10.1380/jsssj.34.368  

    ISSN:0388-5321

    eISSN:1881-4743

  21. Synthesis of LiTaO3 by solvothermal method and their water splitting activity

    S.Takasugi, Y.Matsumoto, K.Tomita, M.Kakihana

    IUMRS-International Conference on Electronic materials (IUMRS-ICEM 2012) 2012年9月

  22. イオン液体膜を介したITO基板上への板状ペンタセン薄膜の形成

    松本 祐司, 萬徳 真志, 武山 洋子

    電子情報通信学会技術研究報告. OME, 有機エレクトロニクス 112 (57) 13-16 2012年5月17日

    出版者・発行元:一般社団法人電子情報通信学会

    ISSN:0913-5685

    詳細を見る 詳細を閉じる

    我々は,イオン液体を介した有機単結晶・薄膜形成技術の開発に取り組んでいる.イオン液体中に,低分子の有機半導体材料を真空蒸着法により気相供給することで,イオン液体中での溶解・析出を伴う有機単結晶の合成が可能である.しかし,薄膜をベースとするデバイス応用には,イオン液体中ではなく,イオン液体を介しつつ,直接基板上に薄膜を成長させることが必要である.本発表では,ITO基板上にイオン液体膜を形成し,ペンタセンの成長をイオン液体の膜内に空間的に制限することで,サイズが10μm以上の板状ペンタセン結晶がITO上に敷き詰められた薄膜を得ることに成功した.

  23. 酸化物単結晶表面の平坦化におけるWetプロセスの化学

    松本祐司

    表面科学 33 (6) 322-327 2012年

    DOI: 10.1380/jsssj.33.322  

  24. ハーフメタル酸化物Sr<sub>2</sub>FeMoO<sub>6</sub>薄膜における物性の膜厚依存性

    門田祥悟, 安井伸太郎, 舟窪浩, 松本祐司, 笹川崇男

    応用物理学関係連合講演会講演予稿集(CD-ROM) 58th 2011年

  25. 様々な基板上へのハーフメタル酸化物Sr<sub>2</sub>FeMoO<sub>6</sub>薄膜の合成と物性

    門田祥悟, 安井伸太郎, 舟窪浩, 松本祐司, 笹川崇男

    応用物理学関係連合講演会講演予稿集(CD-ROM) 58th 2011年

  26. フラックスエピタキシー:C<sub>60</sub>六角板状結晶の生成とその成長過程

    武山洋子, 丸山伸伍, 安井伸太郎, 舟窪浩, 角谷正友, 谷口博基, 伊藤満, 上野啓司, 松本祐司

    応用物理学会学術講演会講演予稿集(CD-ROM) 72nd 2011年

  27. Synthesis and improvement of water-splitting property of Y2Ti2O7 photocatalyst

    Y.Teshirogi, Y.Matsumoto, K.Tomita, Y.Miura, K.Ueda, M.Kakihana

    The 2010 International Chemical Congress of Pacific Basin Societies (Pacifichem 2010) 2010年12月

  28. コンビナトリアル光触媒研究-エピタキシャル薄膜のすすめ-

    松本祐司

    セラミックス 45 (9) 706-710 2010年9月

    出版者・発行元:日本セラミックス協会

    ISSN:0009-031X

  29. フラックス材料のコンビナトリアル探索

    高橋竜太, 松本祐司

    セラミックス 45 (9) 724-727 2010年9月

    出版者・発行元:日本セラミックス協会

    ISSN:0009-031X

  30. 電圧印加抵抗スイッチングを示すAl/Pr<sub>0.7</sub>Ca<sub>0.3</sub>MnO<sub>3</sub>界面の界面構造

    大久保勇男, 菅野弦哉, 原田尚之, 尾嶋正治, 山本剛久, LIPPMAA Mikk, 松本祐司, 大西剛, 鯉沼秀臣

    日本金属学会講演概要 146th 107 2010年3月28日

    ISSN:1342-5730

  31. 強誘電体PbTiO<sub>3</sub>薄膜界面による光析出反応の制御

    高橋竜太, 高橋竜太, 片山正士, 高田真太郎, LIPPMAA Mikk, YOU Chang Chuan, DAHL Oystein, GREPSTAD Jostein, 松本祐司, TYBELL Thomas

    応用物理学関係連合講演会講演予稿集(CD-ROM) 57th 2010年

  32. イオン液体の真空蒸着技術とコンビナトリアル新材料開発への応用

    松本祐司, 丸山伸伍, 武山洋子

    工業材料 58 (10) 60-63 2010年

    出版者・発行元:日刊工業出版プロダクション

    ISSN:0452-2834

  33. 抵抗スイッチングを示す金属-酸化物界面の伝導機構と素子サイズ依存

    大久保 勇男, 菅野 弦哉, 原田 尚之, 尾嶋 正治, 大西 剛, リップマー ミック, 松本 祐司, 鯉沼 秀臣

    日本セラミックス協会 年会・秋季シンポジウム 講演予稿集 2009 (0) 2L19-2L19 2009年9月16日

    出版者・発行元:公益社団法人 日本セラミックス協会

    DOI: 10.14853/pcersj.2009F.0.2L19.0  

    詳細を見る 詳細を閉じる

    金属-絶縁体-金属構造に電圧を印加して発生する抵抗スイッチング現象は、次世代不揮発性メモリーへの応用が期待されている。我々はこれまでに、Pr0.7Ca0.3MnO3(PCMO)薄膜上にさまざまな金属電極を作製し、Al/PCMO界面付近で抵抗スイッチングが発現していることを明らかにした。この抵抗スイッチング現象のメカニズムの解明を最終目的として、Al/PCMO界面における電流-電圧特性の詳細な解析を行った。空間電荷制限電流とプールフレンケル伝導が抵抗スイッチングに関与していることが明らかになり、界面付近の欠陥等における電荷のトラップ-デトラップにより抵抗スイッチングが発現していることが示唆された。当日は、伝導機構の素子サイズ依存等を紹介し、詳細を議論する。

  34. Al/Pr<sub>1-x</sub>Ca<sub>x</sub>MnO<sub>3</sub>界面における抵抗変化現象の素子サイズ依存性

    菅野弦哉, 原田尚之, 大久保勇男, 大西剛, LIPPMAA Mikk, 松本祐司, 鯉沼秀臣, 尾嶋正治

    応用物理学会学術講演会講演予稿集 70th (2) 554 2009年9月8日

  35. 26pYJ-3 フラックスエピタキシー固液界面真空工学に基づく次世代薄膜合成法の開発(新規誘電体設計と究極の試料作製,領域10シンポジウム,領域10,誘電体,格子欠陥,X線・粒子線,フォノン物性)

    松本 祐司

    日本物理学会講演概要集 64 (2) 871-871 2009年8月18日

    出版者・発行元:一般社団法人日本物理学会

    ISSN:1342-8349

  36. Special Issue on Joining Technology for New Metallic Glasses and Inorganic Materials - Selected Papers from the IUMRS International Conference in Asia 2008 (IUMRS-ICA2008) PREFACE

    Akihisa Inoue, Dmitri V. Louzguine, Mikio Fukuhara, Junji Saida, Toshio Kuroda, Fumihiro Wakai, Kenji Ikeuchi, Yuji Matsumoto

    MATERIALS TRANSACTIONS 50 (6) 1235-1235 2009年6月

    出版者・発行元:JAPAN INST METALS

    ISSN:1345-9678

    eISSN:1347-5320

  37. 28pRB-2 ホモエピタキシャルSTO18薄膜の構造相転移(28pRB 誘電体(SrTiO_3系),領域10(誘電体,格子欠陥,X線・粒子線,フォノン物性))

    藤井 康裕, 谷口 博基, 伊藤 満, 片山 正士, 松本 祐司

    日本物理学会講演概要集 64 (0) 951-951 2009年

    出版者・発行元:一般社団法人 日本物理学会

    DOI: 10.11316/jpsgaiyo.64.1.4.0_951_3  

    ISSN:1342-8349

  38. 30aTF-5 磁化誘起SHG法を用いたCo:rutile TiO_2(110)表面磁化の異方性観察(30aTF 領域3,領域9合同 表面界面磁性,領域9(表面・界面,結晶成長))

    渡邊 亮輔, 片山 正士, 鯉沼 秀臣, 田邨 光規, 湯浅 真擁, 八幡 佳成, 水谷 五郎, 鈴木 隆則, 瀬川 勇三郎, 松本 祐司, 山本 雄一

    日本物理学会講演概要集 64 (0) 923-923 2009年

    出版者・発行元:一般社団法人 日本物理学会

    ISSN:1342-8349

  39. CW-IR レーザによるイオン液体の真空蒸着技術の開発

    丸山伸伍, 松本祐司

    レーザー加工学会誌 16 (2) 48-50 2009年

    出版者・発行元:高温学会レーザ加工学会

    ISSN:1881-6797

  40. 光触媒表面の精密制御と有機単分子膜の光分解

    松本祐司

    光化学 40 (2) 114-117 2009年

  41. 金属/Pr<sub>0.7</sub>Ca<sub>0.3</sub>MnO<sub>3</sub>界面型抵抗変化素子における空間電荷制限電流の重要性

    原田尚之, 大久保勇男, 坪内賢太, 組頭広志, 大西剛, LIPPMAA Mikk, 松本祐司, 鯉沼秀臣, 尾嶋正治

    応用物理学会学術講演会講演予稿集 69th (2) 505 2008年9月2日

  42. Metal/Pr<sub>0.7</sub>Ca<sub>0.3</sub>Mn0<sub>3</sub>ショットキー接合における電流‐電圧特性の電極依存性(3)

    原田尚之, 大久保勇男, 組頭広志, 大西剛, 松本祐司, LIPPMAA Mikk, 鯉沼秀臣, 尾嶋正治

    応用物理学会学術講演会講演予稿集 69th (2) 505 2008年9月2日

  43. Metal/Pr<sub>0.7</sub>Ca<sub>0.3</sub>MnO<sub>3</sub>ショットキー接合における電流‐電圧特性の電極依存性(2)

    原田尚之, 大久保勇男, 組頭広志, 大西剛, 片山正士, 松本祐司, LIPPMAA Mikk, 鯉沼秀臣, 尾嶋正治

    応用物理学関係連合講演会講演予稿集 55th (2) 628 2008年3月27日

  44. 人工界面酸化物層を導入した金属/Pr<sub>0.7</sub>Ca<sub>0.3</sub>MnO<sub>3</sub>界面の電流‐電圧特性

    菅野弦哉, 原田尚之, 大久保勇男, 組頭広志, 大西剛, 松本祐司, LIPPMAA Mikk, 鯉沼秀臣, 尾嶋正治

    応用物理学関係連合講演会講演予稿集 55th (2) 628 2008年3月27日

  45. フラックスエピタキシー:酸化物完全単結晶薄膜への挑戦

    松本祐司

    機能材料 28 (3) 21-26 2008年2月5日

  46. フラックスエピタキシー法を用いた自己組織化Bi<sub>4</sub>Ti<sub>3</sub>O<sub>12</sub>ナノプレートの成長機構

    今井彰良, 高橋竜太, 竹内一郎, 松本祐司

    応用物理学会学術講演会講演予稿集 69th (2) 2008年

  47. 24pPSA-46 フェムト秒レーザーを用いた磁化誘起光第二高調波観測システムの構築(ポスターセッション,領域9,表面・界面,結晶成長)

    渡邊 亮輔, 鯉沼 秀臣, 田邨 光規, 湯浅 真擁, 八幡 佳成, 水谷 五郎, 鈴木 隆則, 瀬川 勇三郎, 松本 祐司, 山本 雄一

    日本物理学会講演概要集 63 (0) 889-889 2008年

    出版者・発行元:一般社団法人 日本物理学会

    ISSN:1342-8349

  48. 1ピコリットルのイオン液体を真空蒸着する新技術で切り拓く液体膜の応用と展開

    松本祐司

    WEB Journal (96) 8-11 2008年

  49. Metal/Pr<sub>0.7</sub>Ca<sub>0.3</sub>MnO<sub>3</sub>ショットキー接合における電流‐電圧特性の電極依存性

    原田尚之, 坪内賢太, 大久保勇男, 組頭広志, 大西剛, 片山正士, 松本祐司, LIPPMAA Mikk, 鯉沼秀臣, 尾嶋正治

    応用物理学会学術講演会講演予稿集 68th (2) 652 2007年9月4日

  50. 積層型Metal/Pr<sub>0.7</sub>Ca<sub>0.3</sub>MnO<sub>3</sub>/LaNiO<sub>3</sub>抵抗変化素子の容量特性

    坪内賢太, 大久保勇男, 原田尚之, 組頭広志, 松本祐司, 大西剛, LIPPMAA Mikk, 鯉沼秀臣, 尾嶋正治

    応用物理学関係連合講演会講演予稿集 54th (2) 684 2007年3月27日

  51. Metal/Pr<sub>0.7</sub>Ca<sub>0.3</sub>MnO<sub>3</sub>/LaNiO<sub>3</sub>積層構造における電圧印加抵抗変化特性

    原田尚之, 坪内賢太, 大久保勇男, 組頭広志, 大西剛, 松本祐司, LIPPMAA Mikk, 鯉沼秀臣, 尾嶋正治

    応用物理学関係連合講演会講演予稿集 54th (2) 683 2007年3月27日

  52. 連続発振レーザーMBEによる有機分子組成傾斜薄膜の作製

    柳沼誠一郎, 伊高健治, 松本祐司, 大西剛, LIPPMAA Mikk, 長田貴弘, 知京豊裕, 鯉沼秀臣

    応用物理学関係連合講演会講演予稿集 54th (3) 1289 2007年3月27日

  53. Epitaxial Growth of C60 Thin Films using Continuous-Wave Laser Molecular Beam Epitaxy

    Seiichiro Yaginuma, Kenji Itaka, Masamitsu Haemori, Masao Katayama, Yuji Matsumoto, Hideomi Koinuma

    Mater. Res. Soc. Symp. Proc. 965 0965-S14-06 2007年

  54. 22pPSB-74 Co:TiO_2(110)からの磁化誘起SH光強度の方位角依存性(領域9ポスターセッション,領域9,表面・界面,結晶成長)

    渡邊 亮輔, 鯉沼 秀臣, 田邨 光規, 湯浅 真擁, 八幡 佳成, 水谷 五郎, 鈴木 隆則, 瀬川 勇三郎, 松本 祐司, 山本 雄一

    日本物理学会講演概要集 62 (0) 953-953 2007年

    出版者・発行元:一般社団法人 日本物理学会

    ISSN:1342-8349

  55. 20aPS-46 Co:TiO_2(110)におけるバルク吸収波長領域での磁化誘起SHGの観測(ポスターセッション,領域9,表面・界面,結晶成長)

    渡邊 亮輔, 湯浅 真擁, 八幡 佳成, 水谷 五郎, 鈴木 隆則, 瀬川 勇三郎, 松本 祐司, 山本 雄一, 鯉沼 秀臣

    日本物理学会講演概要集 62 (0) 905-905 2007年

    出版者・発行元:一般社団法人 日本物理学会

    ISSN:1342-8349

  56. DEVELOPMENT OF A VARIABLE TEMPERATURE UHV-LASER MICROSCOPE COMBINED WITH A PULSED LASER DEPOSITION FOR IN SITU STUDIES OF CERAMICS/METALLIC GLASS INTERFACES

    Yuji Matsumoto, Takuma Obata, Miki Hiraoka, Masao Katayama

    CHARACTERIZATION AND CONTROL OF INTERFACES FOR HIGH QUALITY ADVANCED MATERIALS II 198 15-20 2007年

    出版者・発行元:AMER CERAMIC SOC

    ISSN:1042-1122

    詳細を見る 詳細を閉じる

    A new laser microscope (LM) has been designed and developed for in situ observation of metallic glass thin films and their interfaces with oxides. It can operate at various gas pressure and temperature conditions, from UHV(1x10(-8) eforr) to atmosphere and from RT to 1000 degrees C, respectively. The LM system can be connected with a pulsed laser deposition (PLD) system that allows us to directly transfer the sample prepared in the PLD to the LM system without exposing it to air. In order to verify the capability of this LM system, the surface morphology of metallic glass thin films was characterized at various temperature and atmospheric conditions. As a consequence, we succeeded in making the first observation of the dynamic behavior of a metallic glass in liquid droplet form, and also found different behavior of transitions in vacuum.

  57. DEVELOPMENT OF A VARIABLE TEMPERATURE UHV-LASER MICROSCOPE COMBINED WITH A PULSED LASER DEPOSITION FOR IN SITU STUDIES OF CERAMICS/METALLIC GLASS INTERFACES

    Yuji Matsumoto, Takuma Obata, Miki Hiraoka, Masao Katayama

    CHARACTERIZATION AND CONTROL OF INTERFACES FOR HIGH QUALITY ADVANCED MATERIALS II 198 15-20 2007年

    出版者・発行元:AMER CERAMIC SOC

    ISSN:1042-1122

    詳細を見る 詳細を閉じる

    A new laser microscope (LM) has been designed and developed for in situ observation of metallic glass thin films and their interfaces with oxides. It can operate at various gas pressure and temperature conditions, from UHV(1x10(-8) eforr) to atmosphere and from RT to 1000 degrees C, respectively. The LM system can be connected with a pulsed laser deposition (PLD) system that allows us to directly transfer the sample prepared in the PLD to the LM system without exposing it to air. In order to verify the capability of this LM system, the surface morphology of metallic glass thin films was characterized at various temperature and atmospheric conditions. As a consequence, we succeeded in making the first observation of the dynamic behavior of a metallic glass in liquid droplet form, and also found different behavior of transitions in vacuum.

  58. Photo-catalysis effect of III-V nitride film

    Masatorno Sumiya, Keisuke Ohara, Takeo Ohsawa, Yu. Kawai, Masato Shirai, Shunro Fuke, Hideomi Koinurna, Yuji Matsumoto

    PHYSICA STATUS SOLIDI C - CURRENT TOPICS IN SOLID STATE PHYSICS, VOL 4 NO 7 2007 4 (7) 2642-+ 2007年

    出版者・発行元:WILEY-V C H VERLAG GMBH

    DOI: 10.1002/pssc.200674886  

    ISSN:1862-6351

    詳細を見る 詳細を閉じる

    We have studied the photo catalysis effect in III-V nitride film having the potential overall water splitting under UV- or visible light irradiation. It was found that the photo catalysis effect was greater on the surface of GaN film with Ga-face (+c) polarity than that with N-face (-c) polarity. This polarity dependence was discussed in term of band profile caused by the spontaneous polarization. Alloying InN mole fraction with GaN made it possible to generate the photo catalysis effect for visible light in Ill-V nitride film. (c) 2007 WILEY-NCH Verlag GmbH & Co. KGaA, Weinheim.

  59. Photo-catalysis effect of III-V nitride film

    Masatorno Sumiya, Keisuke Ohara, Takeo Ohsawa, Yu. Kawai, Masato Shirai, Shunro Fuke, Hideomi Koinurna, Yuji Matsumoto

    PHYSICA STATUS SOLIDI C - CURRENT TOPICS IN SOLID STATE PHYSICS, VOL 4 NO 7 2007 4 (7) 2642-+ 2007年

    出版者・発行元:WILEY-V C H VERLAG GMBH

    DOI: 10.1002/pssc.200674886  

    ISSN:1862-6351

    詳細を見る 詳細を閉じる

    We have studied the photo catalysis effect in III-V nitride film having the potential overall water splitting under UV- or visible light irradiation. It was found that the photo catalysis effect was greater on the surface of GaN film with Ga-face (+c) polarity than that with N-face (-c) polarity. This polarity dependence was discussed in term of band profile caused by the spontaneous polarization. Alloying InN mole fraction with GaN made it possible to generate the photo catalysis effect for visible light in Ill-V nitride film. (c) 2007 WILEY-NCH Verlag GmbH & Co. KGaA, Weinheim.

  60. フラックスエピタキシー法を用いたScAlMgO4薄膜成長

    石井 誉, 松本 祐司

    2 (No.) 75 2007年

  61. 二酸化チタンヘテロナノ構造の精密設計と新現象・機能探索

    松本祐司, 片山正士

    表面科学 28 (10) 573-578 2007年

    DOI: 10.1380/jsssj.28.573  

  62. Combinatorial experimentation and materials informatics

    Ichiro Takeuchi, Mikk Lippmaa, Yuji Matsumoto

    MRS BULLETIN 31 (12) 999-1003 2006年12月

    出版者・発行元:MATERIALS RESEARCH SOCIETY

    DOI: 10.1557/mrs2006.228  

    ISSN:0883-7694

    詳細を見る 詳細を閉じる

    High-throughput experimentation is effective in systematically producing large and diverse data sets. The marriage of combinatorial materials science and informatics is a natural one, and results are beginning to emerge from the integration of elements of materials informatics with data from combinatorial libraries. We discuss data management issues in high-throughput experimentation and highlight recent examples where data-mining tools are being implemented for extracting knowledge and predicting new compounds, with an emphasis on electronic materials.

  63. Combinatorial experimentation and materials informatics

    Ichiro Takeuchi, Mikk Lippmaa, Yuji Matsumoto

    MRS BULLETIN 31 (12) 999-1003 2006年12月

    出版者・発行元:MATERIALS RESEARCH SOCIETY

    DOI: 10.1557/mrs2006.228  

    ISSN:0883-7694

    詳細を見る 詳細を閉じる

    High-throughput experimentation is effective in systematically producing large and diverse data sets. The marriage of combinatorial materials science and informatics is a natural one, and results are beginning to emerge from the integration of elements of materials informatics with data from combinatorial libraries. We discuss data management issues in high-throughput experimentation and highlight recent examples where data-mining tools are being implemented for extracting knowledge and predicting new compounds, with an emphasis on electronic materials.

  64. 26aYH-8 遷移金属をドープしたTiO_2エピタキシャル膜の磁場中XMCD測定(26aYH 領域3,領域9合同 表面・界面磁性,領域9(表面・界面,結晶成長))

    阿部 仁, 島田 敏宏, 能川 玄之, 雨宮 健太, 太田 俊明, 稲葉 和久, 廣瀬 靖, 古林 寛, 山本 幸生, 一杉 太郎, 松本 祐司, 長谷川 哲也

    日本物理学会講演概要集 61 (2) 770-770 2006年8月18日

    出版者・発行元:一般社団法人日本物理学会

    ISSN:1342-8349

  65. 原子レベルで平坦なエピタキシャルLaNiO<sub>3</sub>薄膜の作製と物性評価

    坪内賢太, 大久保勇男, 組頭広志, 松本祐司, 大西剛, LIPPMAA Mikk, 鯉沼秀臣, 尾嶋正治

    応用物理学関係連合講演会講演予稿集 53rd (2) 643 2006年3月22日

  66. 27pTD-6 低温STM/STS観測による局所擬ギャップ構造の温度依存性(27pTD 高温超伝導(トンネル分光),領域8(強相関系:高温超伝導,強相関f電子系など))

    眞嶋 秀樹, 村中 伸滋, 植田 敦希, 福尾 則学, 一杉 太郎, 島田 敏宏, 岡田 佳憲, 近藤 猛, 生田 博志, 松本 祐司, 長谷川 哲也

    日本物理学会講演概要集 61 (1) 557-557 2006年3月4日

    出版者・発行元:一般社団法人日本物理学会

    ISSN:1342-8349

  67. 28aSC-4 遷移金属をドープしたTiO_2エピタキシャル膜のXAS,XMCD測定(28aSC 領域9,領域3合同 表面・界面磁性,領域9(表面・界面,結晶成長))

    阿部 仁, 島田 敏宏, 能川 玄之, 雨宮 健太, 太田 俊明, 稲葉 和久, 廣瀬 靖, 古林 寛, 山本 幸生, 一杉 太郎, 松本 祐司, 長谷川 哲也

    日本物理学会講演概要集 61 (1) 873-873 2006年3月4日

    出版者・発行元:一般社団法人日本物理学会

    ISSN:1342-8349

  68. フラックスエピタキシー法によるScAlMgO<sub>4</sub>エピタキシャル薄膜の作製

    小畑拓真, 高橋竜太, 高橋竜太, 大久保勇男, 尾嶋正治, 知京豊裕, 中島清美, 鯉沼秀臣, 鯉沼秀臣, 鯉沼秀臣, 片山正士, 片山正士, 松本祐司, 松本祐司

    応用物理学関係連合講演会講演予稿集 53rd (1) 2006年

  69. 30aPS-65 磁化誘起SHG法によるCoを添加したルチルTiO_2(110)の表面磁性の研究(30aPS 領域9ポスターセッション(表面,界面,結晶成長),領域9(表面・界面,結晶成長))

    渡邊 亮輔, 湯浅 真擁, 八幡 佳成, 水谷 五郎, 鈴木 隆則, 瀬川 勇三郎, 松本 祐司, 山本 雄一, 鯉沼 秀臣

    日本物理学会講演概要集 61 (0) 909-909 2006年

    出版者・発行元:一般社団法人 日本物理学会

    ISSN:1342-8349

  70. Combinatorial approach to exploration of a novel fluid oxide flux stable in vacuum for material processing

    Y. Matsumoto, H. Koinuma, Y. Tsuruta, R. Takahashi

    COMBINATORIAL METHODS AND INFORMATICS IN MATERIALS SCIENCE 894 23-+ 2006年

    出版者・発行元:MATERIALS RESEARCH SOC

    ISSN:0272-9172

    詳細を見る 詳細を閉じる

    We explored a new fluid flux stabilized even in the vacuum condition at high temperature by combinatorial pulsed laser deposition (PLD) approach. A small amount of CuO doped in BiOx was found to effectively stabilize BiOx even in 6 Torr O-2 at 800T. The application of this novel Ei-Cu-O flux to the vacuum process lead to the successful fabrication of a single crystal Bi4Ti3O12 film and the establishment of a more reliable process for preparation of an atomically flat LaAlO3(001) substrate.

  71. High-throughput Studies on Photochemical Properties of Transition Metal-Doped SrTiO<SUB>3</SUB> Epitaxial Thin Films

    T. Ohsawa, H. Koinuma, Y. Matsumoto

    Proc.of MRS Fall Meeting 894 LL03-18.1 2006年

  72. Combinatorial approach to exploration of a novel fluid oxide flux stable in vacuum for material processing

    Y. Matsumoto, H. Koinuma, Y. Tsuruta, R. Takahashi

    COMBINATORIAL METHODS AND INFORMATICS IN MATERIALS SCIENCE 894 23-+ 2006年

    出版者・発行元:MATERIALS RESEARCH SOC

    ISSN:0272-9172

    詳細を見る 詳細を閉じる

    We explored a new fluid flux stabilized even in the vacuum condition at high temperature by combinatorial pulsed laser deposition (PLD) approach. A small amount of CuO doped in BiOx was found to effectively stabilize BiOx even in 6 Torr O-2 at 800T. The application of this novel Ei-Cu-O flux to the vacuum process lead to the successful fabrication of a single crystal Bi4Ti3O12 film and the establishment of a more reliable process for preparation of an atomically flat LaAlO3(001) substrate.

  73. High-throughput Studies on Photochemical Properties of Transition Metal-Doped SrTiO<SUB>3</SUB> Epitaxial Thin Films

    T. Ohsawa, H. Koinuma, Y. Matsumoto

    Proc.of MRS Fall Meeting 894 LL03-18.1 2006年

  74. LaTiO<sub>3</sub>導電性ナノワイヤーの輸送特性

    三原尚士, 渋谷圭介, 大西剛, 松本祐司, 鯉沼秀臣, LIPPMAA Mikk

    応用物理学関係連合講演会講演予稿集 52nd (2) 712 2005年3月29日

  75. エピタキシャルPr<sub>0.7</sub>Ca<sub>0.3</sub>MnO<sub>3</sub>薄膜の電流‐電圧特性における電極依存性

    坪内賢太, 大久保勇男, 組頭広志, 尾嶋正治, 伊高建治, 松本祐司, 大西剛, LIPPMAA Mikk, 鯉沼秀臣

    応用物理学関係連合講演会講演予稿集 52nd (2) 722 2005年3月29日

  76. 導電性ペロブスカイト酸化物を用いた極薄膜の輸送特性

    三原尚士, 渋谷圭介, 大西剛, 松本祐司, 鯉沼秀臣, LIPPMAA M

    応用物理学会学術講演会講演予稿集 65th (2) 543 2004年9月1日

  77. 15aPS-63 超高真空・低温・磁場印加型磁気力顕微鏡 (MFM) の開発(領域 9)

    菅谷 英生, 一杉 太郎, 島田 敏宏, 長村 俊彦, 松本 祐司, 長谷川 哲也

    日本物理学会講演概要集 59 (2) 838-838 2004年8月25日

    出版者・発行元:一般社団法人日本物理学会

    ISSN:1342-8349

  78. ペロブスカイト酸化物導電性ナノワイヤーの作製

    三原尚士, 渋谷圭介, 大西剛, 松本祐司, 鯉沼秀臣, LIPPMAA M

    応用物理学関係連合講演会講演予稿集 51st (2) 654 2004年3月28日

  79. ペロブスカイト酸化物表面原子層による光分解反応制御

    大沢健男, 中島和子, 高橋竜太, 松本祐司, 鯉沼秀臣

    応用物理学関係連合講演会講演予稿集 51st (2) 2004年

  80. フラックスエピタキシーにおける薄膜とフラックスの熱力学安定性

    鶴田裕彦, 高橋竜太, 谷川太一, 松本祐司, 鯉沼秀臣

    応用物理学関係連合講演会講演予稿集 51st (2) 2004年

  81. フラックスエピタキシー手法によるBi<sub>4</sub>Ti<sub>3</sub>O<sub>12</sub>単結晶薄膜の作製

    高橋竜太, 鶴田裕彦, 谷川太一, 青山登代美, 中島清美, 知京豊裕, 大谷亮, 川崎雅司, 松本祐司

    応用物理学関係連合講演会講演予稿集 51st (2) 2004年

  82. フラックスエピタキシー法による強誘電体Bi<sub>4</sub>Ti<sub>3</sub>O<sub>12</sub>薄膜の配向制御とナノプレート構造の作製

    高橋竜太, 米沢喜幸, 鶴田裕彦, 青山登代美, 中島清美, 知京豊裕, 松本祐司, 鯉沼秀臣

    応用物理学会学術講演会講演予稿集 65th (2) 2004年

  83. エピタキシャルBi<sub>4</sub>Ti<sub>3</sub>O<sub>12</sub>薄膜の光触媒特性とその配向依存性

    大原敬介, 大沢健男, 高橋竜太, 松本祐司, 鯉沼秀臣

    応用物理学会学術講演会講演予稿集 65th (2) 2004年

  84. 低温走査型マイクロ波顕微鏡を用いた導電性のハイスループット評価

    岡崎壮平, 岡崎紀明, 高橋竜太, 松本祐司, 鯉沼秀臣, 長谷川哲也

    応用物理学関係連合講演会講演予稿集 51st (2) 2004年

  85. フラックスエピタキシー法による単結晶薄膜成長へのアプローチ

    高橋竜太, 谷川太一, 鶴田裕彦, 青山登代美, 中島清美, 知京豊裕, 松本祐司, 鯉沼秀臣

    応用物理学関係連合講演会講演予稿集 51st (2) 2004年

  86. コンビナトリアル固相エピタキシー法による2元及び3元状態図の作製

    谷川太一, 高橋竜太, 鶴田裕彦, 村上真, 竹内一郎, 松本祐司, 鯉沼秀臣

    応用物理学関係連合講演会講演予稿集 51st (2) 2004年

  87. 14aXD-11 磁化誘起 SHG 法を用いた Co・TiO_2 表面の磁性の研究(表面・界面磁性, 領域 3)

    八幡 佳成, Maung S M, 水谷 五郎, 鈴木 隆則, 瀬川 勇三郎, 松本 祐司, 山本 雄一, 鯉沼 秀臣

    日本物理学会講演概要集 59 (0) 401-401 2004年

    出版者・発行元:一般社団法人 日本物理学会

    ISSN:1342-8349

  88. コンビナトリアル薄膜技術と室温透明磁性薄膜の発見

    松本祐司, 村上真, 長谷川哲也

    応用物理 73 (5) 587-592 2004年

    出版者・発行元:応用物理学会

    ISSN:0369-8009

  89. コンビナトリアルPLD-STM 装置の開発と二酸化チタン光触媒表面のナノスケール表面修飾

    大澤健男, 松本祐司, 鯉沼秀臣

    表面科学 25 (11) 678-683 2004年

    DOI: 10.1380/jsssj.25.678  

  90. 電界効果デバイスのための有機分子薄膜の完全エピタキシー

    松本 祐司

    表面科学 : hyomen kagaku = Journal of the Surface Science Society of Japan 24 (12) 786-786 2003年12月10日

    ISSN:0388-5321

  91. 23pTB-1 アナターゼ TiO_2 薄膜における吸収スペクトルの温度依存性

    牧野 哲征, 瀬川 勇三郎, 松本 祐司, 村上 真, 高橋 竜太, 鯉沼 秀臣

    日本物理学会講演概要集 58 (2) 677-677 2003年8月15日

    出版者・発行元:一般社団法人日本物理学会

    ISSN:1342-8349

  92. RECa<sub>4</sub>O(BO<sub>3</sub>)<sub>3</sub>(RE=希土類)系薄膜の蛍光特性とエネルギー伝達に関する考察

    久保田瞳, 山本幸生, 高橋竜太, 吉村政志, 森勇介, 佐々木孝友, 松本祐司, 鯉沼秀臣, KIM T-W

    応用物理学関係連合講演会講演予稿集 50th (2) 2003年

  93. コンビナトリアル手法によるフラックス材料の探索

    高橋竜太, 谷川太一, 山本幸生, 米沢善幸, 知京豊裕, 川崎雅司, 松本祐司, 鯉沼秀臣

    応用物理学関係連合講演会講演予稿集 50th (2) 2003年

  94. Tri-phase-epitaxy法によるBi<sub>4</sub>Ti<sub>3</sub>O<sub>12</sub>薄膜の作製及び評価

    谷川太一, 高橋竜太, 山本幸生, 米沢善幸, 青山登代美, 中島清美, 知京豊裕, 松本祐司, 鯉沼秀臣

    応用物理学関係連合講演会講演予稿集 50th (2) 2003年

  95. コンビナトリアル技術を用いた2元フラックス探索

    山本幸生, 高橋竜太, 谷川太一, 松本祐司, 鯉沼秀臣

    応用物理学関係連合講演会講演予稿集 50th (2) 2003年

  96. TiO<sub>2</sub>ルチル単結晶基板の原子レベル高平坦化

    山本雄一, 高橋亮太, 米沢卓三, 松本祐司, 鯉沼秀臣

    応用物理学関係連合講演会講演予稿集 50th (2) 2003年

  97. Tri-Phase Epitaxy:気相成長における酸化物薄膜の相制御と高品質化へのアプローチ

    松本祐司, 高橋竜太, 谷川太一, 山本幸生, 知京豊裕, 鯉沼秀臣

    応用物理学関係連合講演会講演予稿集 50th (2) 2003年

  98. フラックス固相エピタキシー法によるBi<sub>4</sub>Ti<sub>3</sub>O<sub>12</sub>薄膜の作製及び評価

    谷川太一, 高橋竜太, 山本幸生, 米沢喜幸, 知京豊裕, 松本祐司, 鯉沼秀臣

    応用物理学会学術講演会講演予稿集 64th (2) 2003年

  99. フラックスエピタキシー手法の提案とそのBi<sub>4</sub>Ti<sub>3</sub>O<sub>12</sub>薄膜の作製

    高橋竜太, 谷川太一, 山本幸生, 米沢喜幸, 知京豊裕, 大谷亮, 川崎雅司, 松本祐司, 鯉沼秀臣

    応用物理学会学術講演会講演予稿集 64th (2) 2003年

  100. High-throughput screening of binary and ternary dielectric oxides by combinatorial technology

    H. Koinuma, R. Takahashi, Y. Yamamoto, H. Minami, K. Itaka, Y, Matsumoto, K, Hasegawa, T. Chikyow

    Dielectrics in Emerging Technologies (2003-01) 323-329 2003年

  101. Micro-structural analyses and Magnetic circular dichroism study of Co doped TiO2 thin films

    Y. Matsumoto, M, Murakami T, Hasegawa, T. Chikyow, H. Ofuchi, H. Koinuma

    2003年

  102. High-throughput screening of binary and ternary dielectric oxides by combinatorial technology

    H. Koinuma, R. Takahashi, Y. Yamamoto, H. Minami, K. Itaka, Y, Matsumoto, K, Hasegawa, T. Chikyow

    Dielectrics in Emerging Technologies (2003-01) 323-329 2003年

  103. Micro-structural analyses and Magnetic circular dichroism study of Co doped TiO2 thin films

    Y. Matsumoto, M, Murakami T, Hasegawa, T. Chikyow, H. Ofuchi, H. Koinuma

    2003年

  104. Tri-Phase Epitaxyによる高温超伝導、単結晶薄膜の作製

    高橋竜太, K.S.Yun, 松本祐司, 川崎雅司, 知京豊裕, 鯉沼秀臣

    日本金属学会誌 66 (4) 284-288 2002年4月

    出版者・発行元:JAPAN INST METALS

    DOI: 10.2320/jinstmet1952.66.4_284  

    ISSN:0021-4876

    eISSN:1880-6880

  105. RECOB(RE=希土類)系3成分連続組成傾斜薄膜の一括合成と蛍光特性

    久保田瞳, 高橋竜太, 荒井信之, KIM T-W, 吉村政志, 中尾日六志, 佐々木孝友, 松本祐司, 鯉沼秀臣

    応用物理学会学術講演会講演予稿集 63rd (2) 2002年

  106. 2元および3元組成材料の一括最適化のためのコンビナトリアルマスク設計

    山本幸生, 高橋竜太, 松本祐司, 鯉沼秀臣

    応用物理学会学術講演会講演予稿集 63rd (2) 2002年

  107. コンビナトリアル手法を利用したTri-phase-epitaxy薄膜の高速最適化

    高橋竜太, 松本祐司, 川崎雅司, 鯉沼秀臣

    応用物理学関係連合講演会講演予稿集 49th (1) 2002年

  108. コンビナトリアル光触媒薄膜評価装置の開発

    松本祐司, 大沢健男, 中島和子, 久保田瞳, 高橋竜太, 鯉沼秀臣

    応用物理学会学術講演会講演予稿集 63rd (2) 2002年

  109. マスクパターン操作によるコンビナトリアル3元相図の一括作製

    高橋竜太, 久保田瞳, 谷川太一, 山本幸生, 松本祐司, 鯉沼秀臣

    応用物理学会学術講演会講演予稿集 63rd (2) 2002年

  110. X-ray magnetic circular dichroism for transparent cobalt-doped anatase thin film

    S. Sasaki, N, Shimizu T, Hanashima H. Udagawa, N. Kawamura, M. Suzuki, H. Maruyama, Y. Matsumoto, H. Koinuma

    Acta Crystallogr. A 58 C350 2002年

  111. Nano-structured oxide thin films and combinatorial technology

    H. Koinuma, R. Takahashi, Y. Matsumoto

    International Symposium on Optical Science and Technologies (SPIE’s 47th Annual Meeting) 2002年

  112. コンビナトリアルレーザーMBE装置を用いた高速合成・条件最適化プロセスの確立

    村上真, 高橋竜太, 松本祐司, 福村知昭, M.Lippmaa, 川崎雅司, 鯉沼秀臣

    JST-CREST「単一分子・原子レベルの反応制御」2期チーム終了シンポジウム 2002年

  113. コンビナトリアル超格子チャンバーの開発とペロブスカイト系超格子薄膜の合成と評価

    松本祐司

    鯉田 崇、荒井信之、松本祐司、M. Lippmaa、川崎雅司、鯉沼秀臣 JST-CREST「単一分子・原子レベルの反応制御」2期チーム終了シンポジウム 2002年

  114. Combinatorial Search for Transparent Oxide Diluted Magnetic Semiconductors

    T. Fukumura, M. Kawasaki Zhengwu Ji, H. Kimura, Y. Yamada, M. Haemori, Y. Matsumoto, K. Inaba, M, Murakami, R. Takahashi, T. Hasegawa, H. Koinuma

    Mat. Res. Soc. Symp. Proc. 700 45-54 2002年

  115. Development of combinatorial PLD-STM system for the quick nano-fabrication and evaluation 700, S3.7.1-S3.7.6 (2002)

    Y. Matsumoto, T. Ohsawa, R. Takahashi, H. Koinuma

    Mat. Res. Soc. Symp. Proc. 700 3-11 2002年

  116. High throughput characterization of magnetic semiconductor thin films with a scanning SQUID microscope

    X. J. Fan, M, Murakami, R. Takahashi, T. Koida, Y, Matsumoto T, Hasegawa, T. Fukumura, M. Kawasaki, P. Ahmet, T. Chikyow, H. Koinuma

    Mat. Res. Soc. Symp. Proc. 700 55-60 2002年

    ISSN:0272-9172

    詳細を見る 詳細を閉じる

    Magnetic properties of Co-doped rutile (Ti1-xCoxO2) film in combinatorial composition-spread form have been surveyed by means of a Scanning Superconducting-quantum-interference-device Microscope (SSM). As a consequence, we found magnetic domains in the spatial regions with x>0.05 without external field, giving strong evidence for ferromagnetism with finite spontaneous magnetization. The magnetic moment was monotonously increased with increasing doping level x from 0.05 to ∼ 0.13. On the other hand, it was almost unchanged for x > ∼ 0.13, suggesting that Co does not dissolve into rutile film beyond x ∼ 0.13. The SSM results on the rutile Ti0.95Co0.05O2 thin films with different thickness showed that the magnetic moment is proportional to film thickness, leading to a conclusion that the presently observed ferromagnetism does not result from Co or Co-based oxide particles on the film surface.

  117. コンビナトリアルマテリアルの放射光X線分析による評価法の開発(1)

    中井泉, 福田勝利, 寺田靖子, 福村知昭, 川崎雅司, 松本祐司, 鯉沼秀臣, 高田和典, 渡辺遵

    第15回日本放射光学会年会・放射光科学合同シンポジウム 2002年

  118. High throughput characterization of magnetic semiconductor thin films with a scanning SQUID microscope

    XJ Fan, M Murakami, R Takahasi, T Koida, Y Matsumoto, T Hasegawa, T Fukumura, M Kawasaki, P Ahmet, T Chikyow, H Koinuma

    COMBINATORIAL AND ARTIFICIAL INTELLIGENCE METHODS IN MATERIALS SCIENCE 700 55-60 2002年

    出版者・発行元:MATERIALS RESEARCH SOCIETY

    ISSN:0272-9172

    詳細を見る 詳細を閉じる

    Magnetic properties of Co-doped rutile (Ti1-xCoxO2) film in combinatorial composition-spread form have been surveyed by means of a Scanning Superconducting-quantum-interference-device Microscope (SSM). As a consequence, we found magnetic domains in the spatial regions with x&gt;0.05 without external field, giving strong evidence for ferromagnetism with finite spontaneous magnetization. The magnetic moment was monotonously increased with increasing doping level x from 0.05 to similar to 0.13. On the other hand, it was almost unchanged fort &gt; similar to 0.13, suggesting that Co does not dissolve into rutile film beyond x similar to 0.13. The SSM results on the rutile Ti0.95Co0.05O2 thin films with different thickness showed that the magnetic moment is proportional to film thickness, leading to a conclusion that the presently observed ferromagnetism does not result from Co or Co-based oxide particles on the film surface.

  119. Combinatorial exploration of transparent ferromagnetism in transiton metal doped wide gap oxide semiconductors

    YUJI MATSUMOTO

    CMD 19 CMMP 2002 2002 - 19th General Conference of the EPS Condensed Matter Division & Condensed Matter and Materials Physics 2002年

  120. Development of combinatorial PLD-STM system for the quick nano-fabrication and evaluation

    Y Matsumoto, T Ohsawa, R Takahashi, H Koinuma

    COMBINATORIAL AND ARTIFICIAL INTELLIGENCE METHODS IN MATERIALS SCIENCE 700 3-11 2002年

    出版者・発行元:MATERIALS RESEARCH SOCIETY

    ISSN:0272-9172

    詳細を見る 詳細を閉じる

    A combinatorial PLD-STM system has been developed for quick nano-fabrication and evaluation of epitaxial thin films and catalysts. Through a gate valve, a combinatorial nano-materials library fabricated in a PLD chamber can be transferred to a surface analysis chamber equipped with LEED and STM. The LEED pattern and atomically resolved STM image for systematically varied samples in the library are measured by locating one sample to another at the electron beam and STM probe position. In this way, we have quickly elucidated the initial growth process of SrO on SrTiO3(001) as well as surface structures of transition metal deposited TiO2 anatase. The combinatorial PLD-STM system has been verified to be very efficient technique for the exploration and optimization of nano-materials.

  121. Combinatorial molecular layer epitaxy of Hf based phosphor oxides

    N Arai, TW Kim, H Kubota, Y Matsumoto, H Koinuma

    COMBINATORIAL AND ARTIFICIAL INTELLIGENCE METHODS IN MATERIALS SCIENCE 700 31-36 2002年

    出版者・発行元:MATERIALS RESEARCH SOCIETY

    ISSN:0272-9172

    詳細を見る 詳細を閉じる

    A series of MHfO3: Tm (M =Ca, Sr and Ba) composition spread films and superlattices (SLs) were quickly fabricated on SrTiO3 (001) substrate in the molecular layer-by-layer growth using combinatorial pulsed laser deposition (PLD) under in-situ reflection high-energy electron diffraction (RHEED) monitoring. Crystal structures and luminescence properties of composition-spread and SLs were evaluated by the concurrent X-ray diffractometer and cathode luminescence (CL), respectively. CL properties of the films were found strongly dependent on their composition and stacking sequence. Possible effect of the stress due to the film-substrate interaction on the CL property is discussed.

  122. High throughput optimization of Y-type magnetoplumbite epitaxial thin film growth by combinatorial pulsed laser deposition technique

    Ohkubo, I, Y Matsumoto, M Ohtani, T Hasegawa, K Ueno, K Itaka, A Parhat, T Chikyow, M Kawasaki

    COMBINATORIAL AND ARTIFICIAL INTELLIGENCE METHODS IN MATERIALS SCIENCE 700 61-66 2002年

    出版者・発行元:MATERIALS RESEARCH SOC

    ISSN:0272-9172

    詳細を見る 詳細を閉じる

    Thin films of Y-type magnetoplumbite (Ba2Co2Fe12O22 : Co2Y) with such a huge unit cell length as 43.5 Angstrom has been successfully fabricated for the first time with the aid of combinatorial optimization of pulsed laser deposition process. Planning a thickness gradient Coo buffer layer on MgAl2O4(111) substrate was very effective for prevent the phase separation of Co deficient impurity (BaFe2O4) to reside in the formation of desired Co2Y phase. From the TEM analysis, the Coo buffer layer of optimum thickness was incorporated into the Co2Y film to make the interface with the make an atomically sharp.

  123. Combinatorial exploration of transparent ferromagnetism in transiton metal doped wide gap oxide semiconductors

    YUJI MATSUMOTO

    CMD 19 CMMP 2002 2002 - 19th General Conference of the EPS Condensed Matter Division & Condensed Matter and Materials Physics 2002年

  124. Fabrication and Characterization of Ain Thin Films as Gate Dielectrics for Silicin Devices

    J.H.Song, T. Chikyow, Y.Z.Yoo, P. Ahemet, K, Nakajima T, Naruke, Y, Matsumoto, H. Koinuma

    International Joint Conference on the Applications of Ferroelectrics 2002 (IFFF 2002) 2002年

  125. MHfO3:Tm (M=Sr, Ba, Ca)系薄膜の蛍光XAFS法による評価と光学的特性

    大渕博宣, 荒井信之, 久保田瞳, 金太源, 尾嶋正治, 松本祐司, 鯉沼秀臣

    第15回日本放射光学会年会・放射光科学合同シンポジウム 2002年

  126. Combinatorial molecular layer epitaxy of Hf based phosphor oxides

    N Arai, TW Kim, H Kubota, Y Matsumoto, H Koinuma

    COMBINATORIAL AND ARTIFICIAL INTELLIGENCE METHODS IN MATERIALS SCIENCE 700 31-36 2002年

    出版者・発行元:MATERIALS RESEARCH SOCIETY

    ISSN:0272-9172

    詳細を見る 詳細を閉じる

    A series of MHfO3: Tm (M =Ca, Sr and Ba) composition spread films and superlattices (SLs) were quickly fabricated on SrTiO3 (001) substrate in the molecular layer-by-layer growth using combinatorial pulsed laser deposition (PLD) under in-situ reflection high-energy electron diffraction (RHEED) monitoring. Crystal structures and luminescence properties of composition-spread and SLs were evaluated by the concurrent X-ray diffractometer and cathode luminescence (CL), respectively. CL properties of the films were found strongly dependent on their composition and stacking sequence. Possible effect of the stress due to the film-substrate interaction on the CL property is discussed.

  127. Characterization of magnetic and dielectric properties on Y-type magnetoplumbite epitaxial thin films for high frequency application

    K. Ueno, I. Ohkubo, Y. Matsumoto, N, Okazaki T, Hasegawa K, Itaka M, Kawasaki, H. Koinuma

    Mat. Res. Soc. Symp. Proc. 700 67-71 2002年

  128. Fabrication and Characterization of Ain Thin Films as Gate Dielectrics for Silicin Devices

    J.H.Song, T. Chikyow, Y.Z.Yoo, P. Ahemet, K, Nakajima T, Naruke, Y, Matsumoto, H. Koinuma

    International Joint Conference on the Applications of Ferroelectrics 2002 (IFFF 2002) 2002年

  129. Nano-structured oxide thin films and combinatorial technology

    H. Koinuma, R. Takahashi, Y. Matsumoto

    International Symposium on Optical Science and Technologies (SPIE’s 47th Annual Meeting) 2002年

  130. Combinatorial Search for Transparent Oxide Diluted Magnetic Semiconductors

    T. Fukumura, M. Kawasaki Zhengwu Ji, H. Kimura, Y. Yamada, M. Haemori, Y. Matsumoto, K. Inaba, M, Murakami, R. Takahashi, T. Hasegawa, H. Koinuma

    Mat. Res. Soc. Symp. Proc. 700 45-54 2002年

  131. Characterization of magnetic and dielectric properties on Y-type magnetoplumbite epitaxial thin films for high frequency application

    K Ueno, Ohkubo, I, Y Matsumoto, N Okazaki, T Hasegawa, K Itaka, H Koinuma

    COMBINATORIAL AND ARTIFICIAL INTELLIGENCE METHODS IN MATERIALS SCIENCE 700 67-71 2002年

    出版者・発行元:MATERIALS RESEARCH SOCIETY

    ISSN:0272-9172

    詳細を見る 詳細を閉じる

    Magnetic films for miniaturization of planar inductors operating at GHz frequencies require high resistivity and high ferro-magnetic resonance frequency. Y type magnetoplumbite Ba2Co2Fe12O22(Co2Y) is a candidate material to meet such requirements because it has about 10 Omegam resistivity and resonance frequency higher than 2 GHz. Recently we succeeded in the fabrication of Co2Y epitaxial thin film on MgAl2O4 substrate by combinatorial pulsed laser deposition technique [3]. Here, we report on the magnetic and dielectric properties of this film. The DC resistivity of the film was 7.5 Omegam. The dielectric constant at 1.25 GHz was measured by a microwave microscope to be 11.0. An easy axis coercive force and saturation magnetization were about 145 Oe and 2000 Gauss respectively, being close to those of bulk sample. Furthermore, the magnetic micro domain structures of Co2Y epitaxial thin films were observed by a scanning SQUID microscope.

  132. 広がるコンビナトリアル材料開発の世界

    伊高健治, 長野みか, 大久保勇男, 南秀樹, 久保田瞳, 大澤健男, 松本祐司, 鯉沼秀臣

    JST-CREST「単一分子・原子レベルの反応制御」2期チーム終了シンポジウム 2002年

  133. High throughput optimization of Y-type magnetoplumbite epitaxial thin film growth by combinatorial pulsed laser deposition technique

    Ohkubo, I, Y Matsumoto, M Ohtani, T Hasegawa, K Ueno, K Itaka, A Parhat, T Chikyow, M Kawasaki

    COMBINATORIAL AND ARTIFICIAL INTELLIGENCE METHODS IN MATERIALS SCIENCE 700 61-66 2002年

    出版者・発行元:MATERIALS RESEARCH SOC

    ISSN:0272-9172

    詳細を見る 詳細を閉じる

    Thin films of Y-type magnetoplumbite (Ba2Co2Fe12O22 : Co2Y) with such a huge unit cell length as 43.5 Angstrom has been successfully fabricated for the first time with the aid of combinatorial optimization of pulsed laser deposition process. Planning a thickness gradient Coo buffer layer on MgAl2O4(111) substrate was very effective for prevent the phase separation of Co deficient impurity (BaFe2O4) to reside in the formation of desired Co2Y phase. From the TEM analysis, the Coo buffer layer of optimum thickness was incorporated into the Co2Y film to make the interface with the make an atomically sharp.

  134. SIS接合のためのYBa<sub>2</sub>Fe<sub>3</sub>O<sub>8-δ</sub>絶縁層薄膜の作製

    高橋竜太, 松本祐司, 河野禎市郎, 川崎雅司, 川崎雅司, 鯉沼秀臣, 鯉沼秀臣, 鯉沼秀臣, 鯉沼秀臣

    応用物理学関係連合講演会講演予稿集 48th (1) 2001年

  135. Tri-phase-epitaxy法によるNd<sub>0.7</sub>Ca<sub>0.3</sub>Ba<sub>2</sub>Cu<sub>3</sub>O<sub>7-δ</sub>薄膜の作製

    高橋竜太, 松本祐司, 河野禎市郎, 川崎雅司, 川崎雅司, 川崎雅司, 鯉沼秀臣, 鯉沼秀臣, 鯉沼秀臣, 鯉沼秀臣

    応用物理学会学術講演会講演予稿集 62nd (1) 2001年

  136. High Throughput Research on ZnO Films and Superlattices by Combinatorial Methodology

    M. Kawasaki, A. Ohtomo, K. Tamura, T. Fukumura, Zhengwu Ji, H. Kimura, A. Tsukazaki, H. Saito, C. Hirose, Y. Matsumoto, H. Koinuma, T, Makino H, D. Sun, Y. Se

    13th Int’l Conf. on Crystal Growth in Conjunction with 11th Int’l Conf. on Vapor Growth and Epitaxy 590 2001年

  137. Parallel synthesis and high throughput characterization of ZnO based alloy films, heterostructures and devices

    Y. Matsumoto, M. Kawasaki

    10th Int’l Conf. on Modulated Semiconductor Structures Abstract Booklet O49 2001年

  138. Combinatorial discovery of transparent ferromagnetism in transition metal doped TiO_2_

    Y. Matsumoto, X.-J. Fan T, Hasegawa M, Murakami, R. Takahashi, H. Koinuma, S. Koshihara M, Kawasaki, T. Fukumura M. Kawasaki, P. Ahmet

    Abst. the 2nd Int’l Workshop on Novel Quantum Phenomena in Transition Metal oxides 63 2001年

  139. Parallel Fabrication of Lattice Engineered Materials by Combinatorial Laser MBE

    H. Koinuma, Y, Matsumoto T, Koida M. Lippmaa, M. Kawasaki

    The 4th Pacific Rim Conference on Laser and Electro-Optics Technical Digest (I) 40-4 2001年

  140. Second-harmonic generation in GdxY1-xCa4(BO3)(3) thin films grown by combinatorial laser MBE

    TW Kim, N Arai, Y Matsumoto, M Yoshimura, H Furuya, H Nakao, Y Mori, T Sasaki, H Koinuma

    CLEO(R)/PACIFIC RIM 2001, VOL II, TECHNICAL DIGEST (II) 442-443 2001年

    出版者・発行元:IEEE

    詳細を見る 詳細を閉じる

    We report on the observation of second-harmonic generation in the epitaxial GdxY1-xCa4O(BO3)(3) thin films with atomically smooth surface. Those films exhibit the noncritical phase-matching second-harmonic generation of neodymium-doped yttrium aluminum garnet laser at room temperature.

  141. Atomic-scale growth of anatase thin films by laser molecular beam epitaxy

    Y. Matsumoto, M, Murakami T. Ohsawa, H. Koinuma, M. Kawasaki

    Proc. of the fifth Symp. on Atomic-scale Surface and Interface Dynamics 319-322 2001年

  142. The x-ray diffraction mapping of thin films with concurrent x-ray diffractometer

    M. Ohtani, T. Fukumura, M. Lippmaa, R. Takahashi, Y. Matsumoto, M. Kawasaki, H. Koinuma, K. Omote, T, Kikuchi J. Harada

    Proc. of the fifth Symp. on Atomic-scale Surface and Interface Dynamics 335-338 2001年

  143. Fabrication of transition-metal-doped epitaxial ZnO thin films and their optical and magnetotransport properties

    Zhengwu Jin, T. Fukumura, Y.-Z. Yoo, M, Murakami Y, Matsumoto T, Sekiguchi M, Kawasaki T, Hasegawa, H. Koinuma

    Proc. of the fifth Symp. on Atomic-scale Surface and Interface Dynamics 357-360 2001年

  144. Single Crystalline Structure and Physical Properties of Rba_2_Cu_3_O_7-y_ thin Films Grown by Tri-phase epitaxy

    K-S. Yun, Y, Matsumoto J, H. Song, R. Takahashi, P. Ahmet, T. Chikyow, T, Hasegawa M, Kawasaki, H. Koinuma

    8th International Superconductive Electronics Conference, Osaka, Jun. 19-22 2001年

  145. High Throughput Research on ZnO Films and Superlattices by Combinatorial Methodology

    M. Kawasaki, A. Ohtomo, K. Tamura, T. Fukumura, Zhengwu Ji, H. Kimura, A. Tsukazaki, H. Saito, C. Hirose, Y. Matsumoto, H. Koinuma, T, Makino H, D. Sun, Y. Se

    13th Int’l Conf. on Crystal Growth in Conjunction with 11th Int’l Conf. on Vapor Growth and Epitaxy 590 2001年

  146. Atomic-scale growth of anatase thin films by laser molecular beam epitaxy

    Y. Matsumoto, M, Murakami T. Ohsawa, H. Koinuma, M. Kawasaki

    Proc. of the fifth Symp. on Atomic-scale Surface and Interface Dynamics 319-322 2001年

  147. 透明な磁石の製作に成功

    松本祐司, 鯉沼秀臣

    子供の科学 64 (4) 44-45 2001年

  148. Single Crystalline Structure and Physical Properties of Rba_2_Cu_3_O_7-y_ thin Films Grown by Tri-phase epitaxy

    K-S. Yun, Y, Matsumoto J, H. Song, R. Takahashi, P. Ahmet, T. Chikyow, T, Hasegawa M, Kawasaki, H. Koinuma

    8th International Superconductive Electronics Conference, Osaka, Jun. 19-22 2001年

  149. Parallel synthesis and high throughput characterization of ZnO based alloy films, heterostructures and devices

    Y. Matsumoto, M. Kawasaki

    10th Int’l Conf. on Modulated Semiconductor Structures Abstract Booklet O49 2001年

  150. Atomic-Scale Controlled Growth of Anatase Thin Films by Laser Molecular Beam Epitaxy

    T. Ohsawa, Y, Matsumoto M, Murakami, H. Koinuma, M. Kawasaki, P. Ahmet, K. Nakajima, T. Chikyow

    13th Int’l Conf. on Crystal Growth in Conjunction with 11th Int’l Conf. on Vapor Growth and Epitaxy 548 2001年

    DOI: 10.1143/JJAP.40.L1204  

  151. Atomic-Scale Controlled Growth of Anatase Thin Films by Laser Molecular Beam Epitaxy

    T. Ohsawa, Y, Matsumoto M, Murakami, H. Koinuma, M. Kawasaki, P. Ahmet, K. Nakajima, T. Chikyow

    13th Int’l Conf. on Crystal Growth in Conjunction with 11th Int’l Conf. on Vapor Growth and Epitaxy 548 2001年

    DOI: 10.1143/JJAP.40.L1204  

  152. The x-ray diffraction mapping of thin films with concurrent x-ray diffractometer

    M. Ohtani, T. Fukumura, M. Lippmaa, R. Takahashi, Y. Matsumoto, M. Kawasaki, H. Koinuma, K. Omote, T, Kikuchi J. Harada

    Proc. of the fifth Symp. on Atomic-scale Surface and Interface Dynamics 335-338 2001年

  153. Artificially manipulated hole distribution in La_0.5_Sr_0.5_MnO_3_ films by the construction of [(LaMnO_3_)_m_/(SrMnO_3_)_m_] superlattices

    T. Koida, Y. Abiko, M. Lippmaa, T. Fukumura, K. Itaka, Y, Matsumoto, H. Koinuma, M. Kawasaki

    Proc. of the fifth Symp. on Atomic-scale Surface and Interface Dynamics 343-349 2001年

  154. Fabrication of transition-metal-doped epitaxial ZnO thin films and their optical and magnetotransport properties

    Zhengwu Jin, T. Fukumura, Y.-Z. Yoo, M, Murakami Y, Matsumoto T, Sekiguchi M, Kawasaki T, Hasegawa, H. Koinuma

    Proc. of the fifth Symp. on Atomic-scale Surface and Interface Dynamics 357-360 2001年

  155. Combinatorial discovery of transparent ferromagnetism in transition metal doped TiO_2_

    Y. Matsumoto, X.-J. Fan T, Hasegawa M, Murakami, R. Takahashi, H. Koinuma, S. Koshihara M, Kawasaki, T. Fukumura M. Kawasaki, P. Ahmet

    Abst. the 2nd Int’l Workshop on Novel Quantum Phenomena in Transition Metal oxides 63 2001年

  156. Artificially manipulated hole distribution in La_0.5_Sr_0.5_MnO_3_ films by the construction of [(LaMnO_3_)_m_/(SrMnO_3_)_m_] superlattices

    T. Koida, Y. Abiko, M. Lippmaa, T. Fukumura, K. Itaka, Y, Matsumoto, H. Koinuma, M. Kawasaki

    Proc. of the fifth Symp. on Atomic-scale Surface and Interface Dynamics 343-349 2001年

  157. Parallel Fabrication of Lattice Engineered Materials by Combinatorial Laser MBE

    H. Koinuma, Y, Matsumoto T, Koida M. Lippmaa, M. Kawasaki

    The 4th Pacific Rim Conference on Laser and Electro-Optics Technical Digest (I) 40-4 2001年

  158. Second-harmonic generation in GdxY1-xCa4(BO3)(3) thin films grown by combinatorial laser MBE

    TW Kim, N Arai, Y Matsumoto, M Yoshimura, H Furuya, H Nakao, Y Mori, T Sasaki, H Koinuma

    CLEO(R)/PACIFIC RIM 2001, VOL II, TECHNICAL DIGEST (II) 442-443 2001年

    出版者・発行元:IEEE

    詳細を見る 詳細を閉じる

    We report on the observation of second-harmonic generation in the epitaxial GdxY1-xCa4O(BO3)(3) thin films with atomically smooth surface. Those films exhibit the noncritical phase-matching second-harmonic generation of neodymium-doped yttrium aluminum garnet laser at room temperature.

  159. 透明磁性酸化物のコンビナトリアル開発

    松本祐司, 長谷川哲也, 鯉沼秀臣

    セラミックス 36 (8) 591-593 2001年

  160. コンビナトリアルナノテクノロジーと酸化物透明磁石の開発

    松本祐司, 村上真, 大澤健男, 鯉沼秀臣

    機能材料 21 (9) 45-50 2001年

    出版者・発行元:シ-エムシ-

    ISSN:0286-4835

  161. 23pSB-3 酸化物希薄磁性半導体Zn_<1-x>TM_xO(TM:遷移金属)の磁気光学スペクトル

    安藤 功兒, 斎藤 秀和, 金 政武, 福村 知昭, 松本 祐司, 川崎 雅司, 鯉沼 秀臣

    日本物理学会講演概要集 55 (2) 572-572 2000年9月10日

    出版者・発行元:一般社団法人日本物理学会

    ISSN:1342-8349

  162. 大気圧コールドプラズマを用いた透明導電性薄膜の作成

    須崎嘉文, 鹿間共一, 松本祐司, 鯉沼秀臣

    東京工業大学応用セラミックス研究所共同利用研究報告書 1999 85-86 2000年6月30日

    ISSN:1345-7772

  163. コンビナトリアルレーザーMBE法によるLaAlO<sub>3</sub>(001)上に作成したTiO<sub>2</sub>薄膜の評価

    村上真, 高橋竜太, 松本祐司, 川崎雅司, 川崎雅司, 鯉沼秀臣, 鯉沼秀臣, 鯉沼秀臣

    応用物理学関係連合講演会講演予稿集 47th (2) 2000年

  164. YBa<sub>2</sub>Cu<sub>3</sub>O<sub>7-δ</sub>薄膜のコンビナトリアル合成

    高橋竜太, 藤本英司, 村上真, 松本祐司, 川崎雅司, 川崎雅司, 鯉沼秀臣, 鯉沼秀臣, 鯉沼秀臣, 鯉沼秀臣

    応用物理学会学術講演会講演予稿集 61st (1) 2000年

  165. Combinatorial Solid State Material Science and Technology

    H. Koinuma, H.N. Aiyer, Y. Matsumoto

    Sci. Tech. Adv. Mat. 1 (1) 1-10 2000年

    DOI: 10.1016/S1468-6996(00)00003-6  

    ISSN:1468-6996

  166. Combinatorial synthesis and high throughput evaluation of doped TiO2 thin films for the development of photocatalysts

    Y Matsumoto, M Murakami, ZW Jin, A Nakayama, T Yamaguchi, T Ohmori, E Suzuki, S Nomura, M Kawasaki, H Koinuma

    COMBINATORIAL AND COMPOSITION SPREAD TECHNIQUES IN MATERIALS AND DEVICE DEVELOPMENT 3941 19-27 2000年

    出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING

    ISSN:0277-786X

    詳細を見る 詳細を閉じる

    TiO2 thin films doped with various transition metals were systematically fabricated by combinatorial laser MBE technique. Alternating KrF excimer laser (lambda = 248 nm) ablation of TiO2 and Ti1-x MxO2 (M = transition metal) was employed to deposit combinatorial library of 18 samples for each dopant with different concentrations. Anatase films with c-axis orientation were grown epitaxially on SrTiO3(001) substrate while the rutile phase films with a-axis orientation were on Al2O3(0001) substrate. Solid solubility of transition metals in both the phases was determined by X-ray diffraction. The anatase phase was found to dissolve the transition metals in higher concentrations than rutile phase. The parallel evaluation of the photocatalytic activity of the doped TiO2 in combinatorial libraries was performed with respect to photodecomposition of water in presence of a small amount of oxidizing or reducing agent which induced pH changes on the pixels. The high throughput evaluation of combinatorially deposited photocatalytic thin films was realized by adopting a potentiometric pH field effect transistor for sensing such pH changes.

  167. Optical characterization for combinatorial systems based on semiconductor ZnO

    T Makino, G Isoya, Y Segawa, CH Chia, T Yasuda, M Kawasaki, A Ohtomo, K Tamura, Y Matsumoto, H Koinuma

    COMBINATORIAL AND COMPOSITION SPREAD TECHNIQUES IN MATERIALS AND DEVICE DEVELOPMENT 3941 28-35 2000年

    出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING

    ISSN:0277-786X

    詳細を見る 詳細を閉じる

    We have developed the simultaneous optical measurement method by using the optic fiber bundles specialized for combinatorial samples combined with the arrayed charge coupled devices (CCD). This also can be used for experiments done at cryogenic temperatures. The smoother dependence upon various growth parameters could be obtained by virtue of the combinatorial fabrication method. Our present study revealed that the use of lattice-matched ScAlMgO4 substrates greatly improved the optical (excitonic) properties of epitaxial ZnO layers as well as ZnO-based quantum wells. The improved points by virtue of lattice-matching are as follows; (1) reduction of the nonradiative decay rate of excitons, (2) settlement of the undesired criterion of well-width, the limit to which the relevant quantum confinement can be achieved, (3) bright excitonic photoluminescence at room temperature as the result of increased quantum efficiency.

  168. Magnetic and optical properties of 3d transition metal doped ZnO thin films

    Z.W. Jin, T. Fukumura, Y.Z. Yoo, M, Murakami T, Sekiguchi Y, Matsumoto M, Kawasaki, H. Koinuma

    Abst. The Int'l Conf. on the Physics and Application of Spin-Related Phenomena in Semiconductors 57 2000年

  169. Combinatorial solid state materials science and technology

    H. Koinuma, H. N. Aiyer, Y. Matsumoto

    SCIENCE AND TECHNOLOGY OF ADVANCED MATERIALS 1 (1) 1-10 2000年

    出版者・発行元:TAYLOR & FRANCIS LTD

    DOI: 10.1016/S1468-6996(00)00003-6  

    ISSN:1468-6996

    eISSN:1878-5514

    詳細を見る 詳細を閉じる

    Conventional 'one by one' synthesis approach has been a major rate limiting step in the systematic exploration of increasingly complex materials for the demanding new technologies. New concepts of 'combinatorial chemistry' are presented for the substantially efficient and cost-effective parallel synthesis and optimization of variety of multicomponent compounds as well as artificially designed lattices and devices. Effectiveness of variety of application areas developed by us is discussed with typical examples and brief review of the merits, challenges, current status and the future directions. (C) 2000 Elsevier Science Ltd. All rights reserved.

  170. Combinatorial Synthesis and High Throughput Charactarization of Transition Metal Doped TiO_2_ Thin Film

    M. Murakami, Z.W. Jin, R. Takahashi, Y. Matsumoto M, Kawasaki, H. Koinuma

    Ext. Absts. The 3rd NIMC Int'l Symp. on Photoreaction Control and Photofunctional Materials 194-195 2000年

  171. Investigation of Gd_x_Y_1-x_Ca_4_O(BO_3_)_3_ Thin Film Growth by Laser MBE

    T.W. Kim, N. Arai, Y. Matsumoto, H. Koinuma, H. Furuya, Y. Mori, T. Sasaki

    Abst. The 1st Asian Conf. on Crystal Growth and Crystal Technology 118-119 2000年

  172. Combinatorial synthesis and high throughput evaluation of doped TiO2 thin films for the development of photocatalysts

    Y Matsumoto, M Murakami, ZW Jin, A Nakayama, T Yamaguchi, T Ohmori, E Suzuki, S Nomura, M Kawasaki, H Koinuma

    COMBINATORIAL AND COMPOSITION SPREAD TECHNIQUES IN MATERIALS AND DEVICE DEVELOPMENT 3941 19-27 2000年

    出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING

    ISSN:0277-786X

    詳細を見る 詳細を閉じる

    TiO2 thin films doped with various transition metals were systematically fabricated by combinatorial laser MBE technique. Alternating KrF excimer laser (lambda = 248 nm) ablation of TiO2 and Ti1-x MxO2 (M = transition metal) was employed to deposit combinatorial library of 18 samples for each dopant with different concentrations. Anatase films with c-axis orientation were grown epitaxially on SrTiO3(001) substrate while the rutile phase films with a-axis orientation were on Al2O3(0001) substrate. Solid solubility of transition metals in both the phases was determined by X-ray diffraction. The anatase phase was found to dissolve the transition metals in higher concentrations than rutile phase. The parallel evaluation of the photocatalytic activity of the doped TiO2 in combinatorial libraries was performed with respect to photodecomposition of water in presence of a small amount of oxidizing or reducing agent which induced pH changes on the pixels. The high throughput evaluation of combinatorially deposited photocatalytic thin films was realized by adopting a potentiometric pH field effect transistor for sensing such pH changes.

  173. Optical characterization for combinatorial systems based on semiconductor ZnO

    T Makino, G Isoya, Y Segawa, CH Chia, T Yasuda, M Kawasaki, A Ohtomo, K Tamura, Y Matsumoto, H Koinuma

    COMBINATORIAL AND COMPOSITION SPREAD TECHNIQUES IN MATERIALS AND DEVICE DEVELOPMENT 3941 28-35 2000年

    出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING

    ISSN:0277-786X

    詳細を見る 詳細を閉じる

    We have developed the simultaneous optical measurement method by using the optic fiber bundles specialized for combinatorial samples combined with the arrayed charge coupled devices (CCD). This also can be used for experiments done at cryogenic temperatures. The smoother dependence upon various growth parameters could be obtained by virtue of the combinatorial fabrication method. Our present study revealed that the use of lattice-matched ScAlMgO4 substrates greatly improved the optical (excitonic) properties of epitaxial ZnO layers as well as ZnO-based quantum wells. The improved points by virtue of lattice-matching are as follows; (1) reduction of the nonradiative decay rate of excitons, (2) settlement of the undesired criterion of well-width, the limit to which the relevant quantum confinement can be achieved, (3) bright excitonic photoluminescence at room temperature as the result of increased quantum efficiency.

  174. Synthesis of Gd_1-x_Y_x_Ca_4_(BO_3_)_3_ Thin Films by Pulsed Laser Deposition

    T. W. Kim, N. Arai, Y. Matsumoto, H. Furuya, Y. Mori T, Sasaki H. Koinuma

    Ext. Absts. The 3rd NIMC Int'l Symp. on Photoreaction Control and Photofunctional Materials 154-155 2000年

  175. Investigation of Gd_x_Y_1-x_Ca_4_O(BO_3_)_3_ Thin Film Growth by Laser MBE

    T.W. Kim, N. Arai, Y. Matsumoto, H. Koinuma, H. Furuya, Y. Mori, T. Sasaki

    Abst. The 1st Asian Conf. on Crystal Growth and Crystal Technology 118-119 2000年

  176. High-Throughput Screening of Flux Materials for Single Crystal Growth by Combinatorial Pulsed Laser Deposition

    R. Takahashi, T. Tanigawa, Y. Yamamoto, Y. Yonezawa, Y. Matsumoto, H. Koinuma

    Proc. of MRS Fall Meeting 804 JJ9.21.1-6 2000年

  177. High throughput optimizations of alloy and doped films based on ZnO and parallel synthesis of ZnO/MgxZn1-xO quantum wells using combinatorial laser MBE towards ultraviolet laser

    A Ohtomo, T Makino, K Tamura, Y Matsumoto, Y Segawa, ZK Tang, GKL Wong, H Koinuma, M Kawasaki

    COMBINATORIAL AND COMPOSITION SPREAD TECHNIQUES IN MATERIALS AND DEVICE DEVELOPMENT 3941 70-81 2000年

    出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING

    ISSN:0277-786X

    詳細を見る 詳細を閉じる

    We report high-throughput optimizations for various material parameters of MgxZn1-xO and Zn1-xCdxO alloy films, Al-doped ZnO films, MgxZn1-xO/ZnO single quantum wells and superlattice structures with using combinatorial laser MBE (CL-MBE). Combinatorial chips including nine thin film pixels were grown on lattice-matched ScAlMgO4 (0001) substrates by switching the mask patterns and targets during pulsed laser deposition. For alloy experiments, two chips (two runs) provided us with complete and systematic understanding of the band gap in a range from 3.0 to 3.6 eV. An Al-doped chip revealed systematic variation of the conductivity from 3 to 2 x 10(3) Scm(-1). A single quantum well chip showed clear systematic variation of photoluminescence peak energy as a function of well layer thickness. Two superlattice chips showed clear systematics on the quantum sub-band levels in absorption spectra even at room temperature, giving all desired information being useful for designing an efficient active layer in possible ultraviolet light emitting devices. The excitonic stimulated emissions could be observed even at very low optical pumping at room temperature. The threshold excitation intensity changed in a range of 11 similar to 40 kW/cm(2) and the emission energy can be tuned between 3.2 and 3.4 eV, depending on the well layer thickness and/or the Mg content in the barrier layers. The excitonic stimulated emission could be observed up to 100 degrees C and a characteristic temperature was as high as 87 K for the best sample optimized by the combinatorial approach using only 8 deposition runs carried out in a week.

  178. High throughput optimizations of alloy and doped films based on ZnO and parallel synthesis of ZnO/MgxZn1-xO quantum wells using combinatorial laser MBE towards ultraviolet laser

    A Ohtomo, T Makino, K Tamura, Y Matsumoto, Y Segawa, ZK Tang, GKL Wong, H Koinuma, M Kawasaki

    COMBINATORIAL AND COMPOSITION SPREAD TECHNIQUES IN MATERIALS AND DEVICE DEVELOPMENT 3941 70-81 2000年

    出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING

    ISSN:0277-786X

    詳細を見る 詳細を閉じる

    We report high-throughput optimizations for various material parameters of MgxZn1-xO and Zn1-xCdxO alloy films, Al-doped ZnO films, MgxZn1-xO/ZnO single quantum wells and superlattice structures with using combinatorial laser MBE (CL-MBE). Combinatorial chips including nine thin film pixels were grown on lattice-matched ScAlMgO4 (0001) substrates by switching the mask patterns and targets during pulsed laser deposition. For alloy experiments, two chips (two runs) provided us with complete and systematic understanding of the band gap in a range from 3.0 to 3.6 eV. An Al-doped chip revealed systematic variation of the conductivity from 3 to 2 x 10(3) Scm(-1). A single quantum well chip showed clear systematic variation of photoluminescence peak energy as a function of well layer thickness. Two superlattice chips showed clear systematics on the quantum sub-band levels in absorption spectra even at room temperature, giving all desired information being useful for designing an efficient active layer in possible ultraviolet light emitting devices. The excitonic stimulated emissions could be observed even at very low optical pumping at room temperature. The threshold excitation intensity changed in a range of 11 similar to 40 kW/cm(2) and the emission energy can be tuned between 3.2 and 3.4 eV, depending on the well layer thickness and/or the Mg content in the barrier layers. The excitonic stimulated emission could be observed up to 100 degrees C and a characteristic temperature was as high as 87 K for the best sample optimized by the combinatorial approach using only 8 deposition runs carried out in a week.

  179. Combinatorial Synthesis and High Throughput Charactarization of Transition Metal Doped TiO_2_ Thin Film

    M. Murakami, Z.W. Jin, R. Takahashi, Y. Matsumoto M, Kawasaki, H. Koinuma

    Ext. Absts. The 3rd NIMC Int'l Symp. on Photoreaction Control and Photofunctional Materials 194-195 2000年

  180. Synthesis of Gd_1-x_Y_x_Ca_4_(BO_3_)_3_ Thin Films by Pulsed Laser Deposition

    T. W. Kim, N. Arai, Y. Matsumoto, H. Furuya, Y. Mori T, Sasaki H. Koinuma

    Ext. Absts. The 3rd NIMC Int'l Symp. on Photoreaction Control and Photofunctional Materials 154-155 2000年

  181. Magnetic and optical properties of 3d transition metal doped ZnO thin films

    Z.W. Jin, T. Fukumura, Y.Z. Yoo, M, Murakami T, Sekiguchi Y, Matsumoto M, Kawasaki, H. Koinuma

    Abst. The Int'l Conf. on the Physics and Application of Spin-Related Phenomena in Semiconductors 57 2000年

  182. High-Throughput Screening of Flux Materials for Single Crystal Growth by Combinatorial Pulsed Laser Deposition

    R. Takahashi, T. Tanigawa, Y. Yamamoto, Y. Yonezawa, Y. Matsumoto, H. Koinuma

    Proc. of MRS Fall Meeting 804 JJ9.21.1-6 2000年

  183. 酸化物人工格子のパラレル合成と評価

    川崎雅司, 大西剛, 小宮山大輔, 鯉田崇, 大友明, 福村知昭, 松本祐司, LIPPMAA M, 鯉沼秀臣

    応用物理学会学術講演会講演予稿集 60th (0) 34 1999年9月1日

  184. アメリカ物理学会100周年記念材料開発から原子レベル評価まで―新しい手法による、超伝導研究の新展開―

    松本祐司

    FSST NEWS (73) 1999年

  185. 自己組織化による原子スケールテンプレート法を用いた表面ナノ構造の作成

    松本祐司, 田中虔一

    真空 42 (4) 515-520 1999年

    DOI: 10.3131/jvsj.42.515  

    ISSN:0559-8516

  186. コンビナトリアルケミストリーによる無機材料のハイスループット開発

    松本祐司, 鯉沼秀臣

    セラミックス 34 (5) 373-376 1999年

  187. 28p-YM-13 c(2x2)-N/Cu(100)面上のCo薄膜のSTM観察

    向井 孝三, 松本 祐司, 田中 虔一, 小森 文夫

    日本物理学会講演概要集 53 (2) 409-409 1998年9月5日

    出版者・発行元:一般社団法人日本物理学会

    ISSN:1342-8349

  188. コンビナトリアルレーザーMBE装置の開発

    松本祐司, 村上真, ZENGWU J, 安田真吾, LIPPMAA M, 大西剛, 大橋智, 川崎雅司, 鯉沼秀臣

    応用物理学会学術講演会講演予稿集 59th (2) 533 1998年9月

  189. 化学反応による表面のアトム・リソグラフ

    田中虔一, 松本祐司

    パリティ 13 (12) 34-39 1998年

    出版者・発行元:丸善

    ISSN:0911-4815

  190. 表面新物質の合成とその物性

    松本祐司, 田中虔一

    表面科学 19 (10) 13-20 1998年

    出版者・発行元:The Surface Science Society of Japan

    DOI: 10.1380/jsssj.19.635  

    ISSN:0388-5321 1881-4743

    詳細を見る 詳細を閉じる

    Patterning of metal surfaces by using chemical reactions is a promissing method for the atomic-scale surface fabrica-tion. In this paper we present patterning reactions involving self-assembly processes with two examples: (1) (-Cu-O-) on Ag(110), which is prepared using such a chemical reaction as (-Ag-O-)+Cu→(-Cu-O-)+Ag on Ag(110) and the de-composition of (-Cu-O-) strings on Ag(110) forming a uniform size Cu<SUB>6</SUB> cluster; (2) Depositing Ni on c(2×2)-N Cu (100), where Ni thin films with an average size of 50Å are grown at the crossing of the boundaries of c(2×2)-N patches. In addition, we also show HREELS and ARUPS data in the (-Cu-O-) Ag(110) surface.

  191. Formation of Cu<SUB>6</SUB> clusters on a Ag(110)surface

    Yuji Okawa, Yuji Matsumoto, Ken-ichi Tanaka

    RIKEN Review (17) 37-38 1998年

  192. Acoustic wave enhancement of the catalytic oxidation of carbon monoxide over Pt{110}

    S Kelling, T Mitrelias, Y Matsumoto, VP Ostanin, DA King

    JOURNAL OF CHEMICAL PHYSICS 107 (14) 5609-5612 1997年10月

    出版者・発行元:AMER INST PHYSICS

    ISSN:0021-9606

    詳細を見る 詳細を閉じる

    Clear evidence for the nonthermal acoustic wave enhancement of a catalytic reaction over a single crystal metal surface under controlled conditions is provided in this Letter. Data demonstrating a fourfold increase in the rate of CO oxidation over a thin Pt{110} catalyst bonded onto the surface of a piezoelectric interdigital transducer is discussed here together with a possible mechanism for this effect. (C) 1997 American Institute of Physics.

  193. 8p-B-4 Cu(100)面上のc(2x2)-N超周期ドメイン構造上に生成するNiアイランドの形態

    松本 祐司, 田中 虔一

    日本物理学会講演概要集 52 (2) 381-381 1997年9月16日

    出版者・発行元:一般社団法人日本物理学会

    ISSN:1342-8349

  194. 8p-B-3 Cu(001)-(4x4)-Li表面のSTMによる観察

    水野 清義, 栃原 浩, 松本 祐司, 田中 虔一

    日本物理学会講演概要集 52 (2) 380-380 1997年9月16日

    出版者・発行元:一般社団法人日本物理学会

    ISSN:1342-8349

  195. Structure and catalysis of Rh-Pt(100), Rh-Pt(110), Pt-Rh(100), and Pt-Rh(110) surfaces prepared by electrochemical metal deposition

    K Tanaka, Y Okawa, A Sasahara, Y Matsumoto

    SOLID-LIQUID ELECTROCHEMICAL INTERFACES 656 245-273 1997年

    出版者・発行元:AMER CHEMICAL SOC

    ISSN:0097-6156

    詳細を見る 詳細を閉じる

    Structure and catalysis of Rh/Pt(100), Rh/Pt(110), Pt/Rh(100) and Pt/Rh(110) surfaces prepared by electrochemical deposition were studied. Rh/Pt(100) heated in O-2 at T &gt; 340 K gives a clear p(3x1) LEED pattern. Similar p(3x1) structure is established on Pt/Rh(100) by heating in O-2 at ca. 600 K. Catalytic activity for NO + H-2 is markedly enhanced by the formation of p(3x1) structure. Rh/Pt(110) and Pt/Rh(100) surfaces are also activated by the chemical reconstruction caused by O-2 or NO. STM image proved that the p(3x1) Pt0.25Rh0.75(100) surface is composed of combined array of one Rh-O and two Pt rows along the &lt; 011 &gt; directions, which is responsible for catalysis of NO + H-2 reaction.

  196. The growth mechanism of(-Cu-O-)strings on Ag(110)studied by STM, XPS and HREELS

    Y. Matsumoto, K. Sakamoto, Y. Okawa, S. Suto

    J. Chem. Phys. 107 (23) 10185 1997年

  197. Acousticwave enhancement of the catalyticoxidation of carbonmonoxideover Pt(110)

    S. Kelling, T. Mitrelias, Y. Matsumoto, V.P. Ostanin, D.A. King

    J. Chem. Phys. communication 107 (14) 5609 1997年

  198. Influence of acoustic wave excitation on CO oxidation over a Pt{110} single crystal

    S Kelling, T Mitrelias, Y Matsumoto, VP Ostanin, DA King

    FARADAY DISCUSSIONS 107 435-444 1997年

    出版者・発行元:ROYAL SOC CHEMISTRY

    ISSN:0301-7249

    詳細を見る 詳細を閉じる

    A unique ultra-high vacuum (UHV) compatible excitation system combined with an advanced ultra-high amplitude and frequency resolution acoustic spectrometer has been designed and constructed to permit accurate studies of the fundamental mechanism by which acoustic excitation influences heterogeneous catalytic reactions. A clean Pt{110} thin film single-crystal catalyst was excited with low-energy acoustic waves (Rayleigh waves) under high vacuum and UHV conditions to increase the reaction rate for carbon monoxide oxidation. A remarkable six-fold increase in the chemical activity was observed. By using a new, very accurate method to monitor the sample temperature using high-resolution acoustic wave resonance spectroscopy (HRAWRS), a non-thermal acoustic-wave-induced enhancement of the reaction rate is clearly demonstrated. The pressure and temperature dependences of the enhancement provide some insight into the mechanism by which acoustic waves enhance catalytic reactions on solid surfaces.

  199. The growth mechanism of(-Cu-O-)strings on Ag(110)studied by STM, XPS and HREELS

    Y. Matsumoto, K. Sakamoto, Y. Okawa, S. Suto

    J. Chem. Phys. 107 (23) 10185 1997年

  200. Influence of acoustic wave excitation on CO oxidation over a Pt{110} single crystal

    S Kelling, T Mitrelias, Y Matsumoto, VP Ostanin, DA King

    FARADAY DISCUSSIONS 107 435-444 1997年

    出版者・発行元:ROYAL SOC CHEMISTRY

    ISSN:0301-7249

    詳細を見る 詳細を閉じる

    A unique ultra-high vacuum (UHV) compatible excitation system combined with an advanced ultra-high amplitude and frequency resolution acoustic spectrometer has been designed and constructed to permit accurate studies of the fundamental mechanism by which acoustic excitation influences heterogeneous catalytic reactions. A clean Pt{110} thin film single-crystal catalyst was excited with low-energy acoustic waves (Rayleigh waves) under high vacuum and UHV conditions to increase the reaction rate for carbon monoxide oxidation. A remarkable six-fold increase in the chemical activity was observed. By using a new, very accurate method to monitor the sample temperature using high-resolution acoustic wave resonance spectroscopy (HRAWRS), a non-thermal acoustic-wave-induced enhancement of the reaction rate is clearly demonstrated. The pressure and temperature dependences of the enhancement provide some insight into the mechanism by which acoustic waves enhance catalytic reactions on solid surfaces.

  201. Pt-Rh(100)面上のp(3x1)-O構造のSTMによる研究

    松本 祐司, 大川 祐司, 田中 虔一

    日本物理学会講演概要集. 秋の分科会 1996 (2) 634-634 1996年9月13日

    出版者・発行元:一般社団法人日本物理学会

  202. HREELSとSTMの複合測定によるCu‐O/Ag(110)系の研究

    松本祐司, 坂本一之, 大川祐司, 須藤彰三, 田中けい一

    日本物理学会講演概要集(年会) 51st (2) 552 1996年3月

    ISSN:1342-8349

  203. 金属表面における疑似化合物の生成とその自己秩序化

    田中虔一, 大川祐司, 松本祐司

    日本物理学会誌 50 (12) 965-968 1995年

    出版者・発行元:一般社団法人日本物理学会

    DOI: 10.11316/butsuri1946.50.965  

    ISSN:0029-0181

  204. 5p-Q-6 Ag(110)面上のCu-O一時元化合物の生成とその配列

    松本 祐司, 大川 祐司, 田中 虔一

    日本物理学会講演概要集. 秋の分科会 1994 (2) 439-439 1994年8月16日

    出版者・発行元:一般社団法人日本物理学会

  205. Improvements of shape memory effect and damping in rapidly solidified TiNiCu alloys

    Y FURUYA, HM KIMURA, M MATSUMOTO, T MASUMOTO

    SHAPE MEMORY MATERIALS '94 283-288 1994年

    出版者・発行元:INT ACADEMIC PUBL

︎全件表示 ︎最初の5件までを表示

書籍等出版物 26

  1. Handbook of Silicon Carbide Materials and Devices

    Yuji Matsumoto

    Taylor & Francis Group 2023年6月

  2. 液相からの結晶成長入門 : 育成技術と評価方法

    日本フラックス成長研究会, 吉川, 彰, 横田, 有為, 我田, 元

    日刊工業新聞社 2021年12月

    ISBN: 9784526081774

  3. 2020版 薄膜作製応用ハンドブック

    松本 祐司, 丸山伸伍

    NTS 2020年2月

  4. 最新 実用真空技術総覧

    松本祐司

    NTS 2019年2月

  5. 電気化学・インピーダンス測定の データ解析手法と事例集

    松本祐司

    (株)技術情報協会 2018年12月

  6. イオン液体を用いた真空材料プロセス

    丸山伸伍, 松本祐司

    2017年10月

  7. Laser Deposition of Nano-ionic Liquids and Their Process Applications in a Vacuum

    Y.Matsumoto, S.Maruyama

    RSC Publishing 2017年9月20日

  8. 表面・界面技術ハンドブック

    松本祐司

    NTS出版 2016年

  9. Oxide Thin Film Technology: Growth and Applications

    Y.Matsumoto, R.Takahashi

    Transworld Res Network 2010年

  10. 実験化学講座 第5版 無機化合物

    2005年

  11. 実験化学講座 第5版 ナノテクノロジーの化学

    2005年

  12. 実験化学講座〈23〉無機化合物

    松本祐司

    2005年

  13. 実験化学講座〈28〉ナノテクノロジーの化学

    松本祐司

    2005年

  14. コンビナトリアルテクノロジー 明日を開く‘もの作り’の新世界

    松本祐司

    丸善株式会社 2004年8月30日

  15. コンビナトリアルテクノロジー 明日を開く‘ものつくり’の世界

    丸善 2004年

  16. 次世代エレクトロニクス薄膜技術

    松本祐司

    シーエムシー出版 2003年5月

  17. 「次世代エレクトロニクス薄膜技術」 第6章コンビナトリアルテクノロジー-集積化薄膜技術による材料開発の革新

    株式会社シーエムシー出版 2003年

  18. イオン工学ハンドブック

    松本祐司

    イオン工学研究所 2003年

  19. 酸化物エレクトロニクス

    松本祐司

    培風館 2001年10月

  20. In-situ Microscopy in Materials Research Leading International Research in Electron and Scanning Probe Microscopy

    Kluwer Academic Publishers 1999年

  21. In-situ Microscopy in Materials Research Leading International Research in Electron and Scanning Probe Microscopy

    Kluwer Academic Publishers 1999年

  22. Solid-Liquid Electrochemical Interfaces

    ACS SYMPOSIUM SERIES 1999年

  23. Solid-Liquid Electrochemical Interfaces

    ACS SYMPOSIUM SERIES 1999年

  24. SOLID-LIQUID ELECTROCHEMICAL INTERFACES

    K.Tanaka, Y.Okawa, A.Sasahara, Y.matsumoto

    American Chemical Society 1997年

  25. In-Situ Microscopy in Materials Research: Leading International Research in Electron and Scanning Probe Microscopies

    K.Tanaka, Y.Matsumoto, T.Fujita, Y.Okawa

    Kluwer Academic Publishers 1997年

  26. ナノテクノロジーへの道を拓く「イオン工学ハンドブック」

︎全件表示 ︎最初の5件までを表示

講演・口頭発表等 81

  1. 酸化物エピタキシー技術と新物質開発

    松本 祐司

    強的秩序とその操作に関わる第11回夏の学校 2020年9月7日

  2. ナノイオン液体を介した真空蒸着による2,2′:5′,2″-テルチオフェン結晶薄膜の多形制御

    松本祐司, 大河原奎佑, 丸山伸伍

    第14回日本フラックス成長研究発表会 2019年12月20日

  3. Electropolymerization of polythiophene Films from Terthiophene Gas Transported into Ionic Liquid in a Vacuum 招待有り

    松本 祐司

    International Symposium on Integrated Molecular/Materials Science and Engineering (IMSE-10) 2019年7月5日

  4. 多結晶性イオン液体薄膜の作製とその固液相転移とイオン伝導

    松本 祐司, 吉井 彩, 丸山 伸伍, 小金澤, 智之, 鳥屋部, 果穂, 高澤 亮二

    第66回応用物理学会春季学術講演会 2019年3月10日

  5. 新規Si-Pt フラックスを用いた4H-SiC 薄膜のPLD 成長

    大住亜朱香, 中野倖太, 山王堂尚輝, 丸山伸伍, 松本祐司

    第13 回日本フラックス成長研究発表会 2018年12月14日

  6. 4H-SiC溶液成長中におけるナノスケールステップの動的挙動観察 招待有り

    丸山伸伍, 松本祐司

    第47回結晶成長国内会議(JCCG-47)シンポジウム「次世代産業を担う機能性結晶材料と結晶成長技術」 2018年11月1日

  7. 高温真空レーザー顕微鏡を用いたSiC溶液成長界面のナノスケールステップダイナミクス

    日本物理学会2018年秋季大会 2018年9月11日

  8. 固液界面真空プロセス 招待有り

    松本 祐司

    日本学術振興会 第131委員会 第290回研究会「最戦乱薄膜作製技術-AI支援ファブオペレーション及び気相・液相を介する薄膜プロセスとin-situ観測」 2018年6月7日

  9. 高品質4H-SiC 単結晶薄膜の高速成長

    第12回日本フラックス成長研究発表会 2017年12月8日

  10. 固液界面真空プロセスが拓く新しいものづくり技術

    応用物理学会 有機分子・バイオエレクトロニクス分科会講習会 2017年11月22日

  11. 酸化物エピタキシーと表面化学

    第9回 岩澤コンファレンス 2017年11月8日

  12. SiC溶液成長界面のナノスケールダイナミクスと高品質SiC薄膜の高速成長

    日本セラミックス協会 第30回秋季シンポジウム 2017年9月19日

  13. SiC溶液成長界面のダイナミクスと高品質SiC薄膜の高速成長

    田中シンポジウム2017 2017年6月3日

  14. イオン液体の真空化学プロセス

    平成29年度イオン液体研究会 2017年5月25日

  15. Nano Science of Ionic Liquids and their Chemical Process Applications in a Vacuum

    東京大学理学部化学教室 雑誌会 2017年5月8日

  16. SiC単結晶薄膜溶液成長における不純物添加と多形制御

    日本表面科学会東北・北海道支部講演会 2017年3月9日

  17. State-of-the Art Precision Oxide Semiconductor Electrochemistry ~ Revival of UHV-Electrochemistry Approach in Material Science ~ 国際会議

    International Symposium on Dynamic Process of Chemical Reaction and Catalysis on Surfaces 2016年12月22日

  18. 真空プロセスとの融合が可能にするフラックス成長技術の新展開

    平成28年度 4大学間連携若手研究者育成研究会 2016年12月10日

  19. 真空蒸着法によるイオン液体膜を介したKBr(111)結晶の成長機構

    第11回日本フラックス成長研究発表会 2016年12月9日

  20. アナターゼTiO2エピタキシャル薄膜のPLD合成とin situ測定によるフラットバンド電位の膜厚依存性

    2016年真空・表面科学合同講演会 2016年11月29日

  21. A New Route to One-pot Synthesis of Porous Polyurea Films by Vapor Deposition Polymerization in Ionic Liquid 国際会議

    IMSE-9 2016年10月13日

  22. Epitaxial growth of SiC films via Si-Ni flux by pulsed laser deposition 国際会議

    EMN 3CG 2016 2016年9月4日

  23. 酸化物エピタキシーと表界面ナノエンジニアリング

    表面技術協会第134回講演大会 2016年9月1日

  24. 高温真空レーザー顕微鏡で見るSiC薄膜溶液成長界面のダイナミクス

    平成27年度日本表面科学会東北・北海道支部学術講演会 2016年3月9日

  25. 真空電気化学アプローチによる酸化物半導体界面の物性評価

    第75回応用物理学会秋季学術講演会「固液界面を使った新しい酸化物エレクトロニクス:化学とデバイスの融合」 2014年9月18日

  26. 真空電気化学手法によるTiO<SUB>2</SUB>単結晶・薄膜表界面の欠陥解析

    2013年度後期 物性研究所 短期研究会「エネルギーと新材料の物性・物質科学」 2013年11月11日

  27. Nano-Engineering of Ionic Liquids and their Applications to Material Processing in Vacuum 国際会議

    Internatinal Conference on Nano Science and Nano Technology (ICNST)2013 2013年11月7日

  28. 酸化物半導体の真空電気化学

    物性研究所研究会「Polar Oxides for Energy Conversion」 2013年6月26日

  29. イオン液体と分子エレクトロニクス~真空中での結晶成長と物性評価の革新技術

    M&BE研究会「有機分子・バイオエレクトロニクスの新たな挑戦」 2013年6月14日

  30. 光触媒作用はなぜ再現しないことが多いか

    第32回 表面科学学術講演会 2012年11月20日

  31. イオン液体を介した真空蒸着法による有機単結晶・薄膜の作製

    第42回 結晶成長国内会議 2012年11月9日

  32. Oxygen Diffusion and Vacancy-formation in Oxide Epitaxy 国際会議

    The Seventh Multifunctional Materials Workshop (MFM-7) 2012年8月5日

  33. イオン液体を使った薄膜形成技術の開発

    平成24年度 イオン液体研究会 2012年5月25日

  34. UHV-電気化学複合装置を用いた酸化物半導体単結晶・薄膜電極の研究

    2011年度後期 物性研究所 短期研究会「エネルギー変換の物性科学」 2011年11月14日

  35. Electrochemical approach to oxide electronics 国際会議

    MFM-6 2011年7月31日

  36. Crystal growth in a vacuum with ionic liquids 国際会議

    The 5<SUP>th</SUP> International Symposium on Integrated Molecular /Materials Engineering (ISIMME-5) 2010年9月20日

  37. Flux-mediated Epitaxy of complex Oxides 国際会議

    12<SUP>th</SUP> International Ceramics Congress 2010年6月6日

  38. Nano-engineering of Bi<SUB>4</SUB>Ti<SUB>3</SUB>O<SUB>12</SUB> ferroelectric thin films via fiux-mediated epitaxy 国際会議

    第19回 日本MRS学術シンポジウム 2009年12月7日

  39. Epilayer Control of Photocatalysis at Well-defined Oxide Surface and Interface 国際会議

    北海道大学触媒化学研究センター創立20周年国際シンポジウム 2009年12月7日

  40. Self-template Growth of Ferroelectric Bi<SUB>4</SUB>Ti<SUB>3</SUB>O<SUB>12</SUB> Nano-plate Array 国際会議

    日韓セラッミクス:第26回日韓国際セラミックスセミナー 2009年11月24日

  41. 酸化チタン電界効果トランジスタの開発とその表面界面に関わる周辺技術

    次世代デバイス開発を拓く表面ナノテクノロジー研究会 2009年11月20日

  42. フラックスエピタキシー:固液界面真空工学に基づく次世代薄膜合成法の開発

    日本物理学会 2009秋季大会 2009年9月25日

  43. High-throughput IR-laser Deposition & Laser Microscope Imaging of Ionic Liquids in Vacuum 国際会議

    S.Maruyama

    2009 MRS Spring Meeting 2009年4月15日

  44. Nano Science & Engineering of Ionic Liquid in UHV process 国際会議

    S.Maruyama

    The 3<SUP>rd</SUP> International Symposium on Integrated Molecular /Materials Engineering (ISIMME-3) 2008年11月6日

  45. 26pWQ-3 Bi2212の低温磁場下STM/STS観察VI(26pWQ 磁束量子系II(ナノ構造・電子状態),領域8(強相関係:高温超伝導,強相関f電子系など))

    福尾 則学, 一杉 太郎, 内田 智史, 下山 淳一, 岸尾 光二, 松本 祐司, 長谷川 哲也

    日本物理学会講演 2008年

  46. Field-induced resistance switching at metal/perovskite manganese oxide interface

    Mater.Sci.Eng.B 2008年

  47. Field-induced resistance switching at metal/perovskite manganese oxide interface

    Mater.Sci.Eng.B 2008年

  48. Photochemical switching of ultrathin PbTiO3 films

    Appl. Phys. Lett, 2008年

  49. フラックスエピタキシー:酸化物完全単結晶薄膜への挑戦

    2008年

  50. Photochemical switching of ultrathin PbTiO3 films

    Appl. Phys. Lett, 2008年

  51. Molecular Layer-by-Layer Growth of C60 Thin Films by Continuous-Wave Infrared Laser Deposition

    Applied Physics Express 2008年

  52. Molecular Layer-by-Layer Growth of C60 Thin Films by Continuous-Wave Infrared Laser Deposition

    Applied Physics Express 2008年

  53. General Application of Solid-Liquid Interface to Nano Materials Processing in Vacuum

    The 2<SUP>nd</SUP> International Symposium on Integrated Molecular /Materials Engineering (ISIMME-2) 2007年10月25日

  54. ナノ構造制御された酸化物単結晶薄膜表面・ヘテロ界面の光触媒作用

    第100回 触媒討論会 2007年9月17日

  55. Ultra-quality of Bi<SUB>4</SUB>Ti<SUB>3</SUB>O<SUB>12</SUB> ferroelectric thin films via fiux-mediated epitaxy 国際会議

    European Multifunctional Materials WS 2007年6月17日

  56. A New Approach to Investigation of photocatalysis on Atomically Designed Oxide Sueface and Interface 国際会議

    5<SUP>th</SUP> International WS of Oxide Surfaces 2007年1月7日

  57. 21pWF-3 Bi2212の低温磁場下STM/STS観察 V(21pWF 磁束量子系II(ジョセフソン接合,トンネル分光),領域8(強相関系:高温超伝導,強相関f電子系など))

    福尾 則学, 一杉 太郎, 内田 智史, 下山 淳一, 岸尾 光ニ, 松本 祐司, 長谷川 哲也

    日本物理学会講演 2007年

  58. Epitaxial Growth of C60 Thin Films using Continuous-Wave Laser Molecular Beam Epitaxy

    Mater. Res. Soc. Symp. Proc. 2007年

  59. Continuous wave infrared laser deposition of organic thin films

    J.of Phys. Conf. Series 2007年

  60. Epitaxial Growth of C60 Thin Films using Continuous-Wave Laser Molecular Beam Epitaxy

    Mater. Res. Soc. Symp. Proc. 2007年

  61. Continuous wave infrared laser deposition of organic thin films

    J.of Phys. Conf. Series 2007年

  62. 次世代メタルゲート材料としてのアモルファス合金の探査

    第54回応用物理学関係連合講演会 2007年

  63. 超高品質酸化物単結晶薄膜への挑戦

    日本電子材料技術協会 第43回秋季講演大会 2006年10月19日

  64. 30aUE-7 Bi2212の低温磁場下STM/STS観察III(30aUE 磁束量子系(磁束電子構造),領域8(強相関系:高温超伝導,強相関f電子系など))

    福尾 則学, 眞嶋 秀樹, 一杉 太郎, 島田 敏宏, 内田 智史, 下山 淳一, 岸尾 光二, 松本 祐司, 長谷川 哲也

    日本物理学会講演 2006年

  65. Combi approach to nanosurface chemistry 国際会議

    NIST-NIMS Combinatorial Nanomaterials Symposium 2005年12月5日

  66. Combinatorial Approach to exploration of a novel fluid oxide fiux stable in vacuum for material processing 国際会議

    MRS Fall Meeting 2005年11月28日

  67. Atomic-Scale control of Ceramics Interface and Exploration of new Nanostructures by Combinatorial Approach 国際会議

    PAC RIM 6 2005年9月14日

  68. High-throughput surface and interface for thin film-based photocatalysts 国際会議

    GRC Combinatorial & High Throughput Materials Science 2005年8月16日

  69. 19aYH-6 Bi2212の低温磁場下STM/STS観察II(磁束量子系(相図・可視化・電子状態),領域8(強相関系 : 高温超伝導,強相関f電子系など))

    福尾 則学, 眞嶋 秀樹, 一杉 太郎, 島田 敏宏, 内田 智史, 下山 淳一, 岸尾 光二, 松本 祐司, 長谷川 哲也

    日本物理学会講演 2005年

  70. 24pWA-3 Bi2212の低温磁場下STM/STS観察(高温超伝導(トンネル分光・輸送特性),領域8(強相関系:高温超伝導,強相関f電子系など))

    福尾 則学, 長谷川 哲也, 眞嶋 秀樹, 木野田 剛, 一杉 太郎, 島田 敏宏, 清水 圭輔, 下山 淳一, 岸尾 光二, 松本 祐司

    日本物理学会講演 2005年

  71. High-throughput surface and interface engineering for photo-excited electron/hole transport process 国際会議

    Third Japan-US Workshop on Combinatorial Materials Science and Technology 2004年12月8日

  72. Flux-mediated Epitaxy:New approach to single crystal quality of complex oxide films in vapor phase epitaxy 国際会議

    ICCG-14,ICVGE-12 2004年8月9日

  73. High-throughput synthesis and screening of thin film libraries by combinatorial laser beam epitaxy method 国際会議

    The 7<SUP>th</SUP> World Multiconference on Systemics,Cybernetics and Informatics 2003年7月27日

  74. Combinatorial Approach for Nano-Scale Fabrication and Understanding of Surface and Interface 国際会議

    5th Annual COMBI 2003-Combinatorial Approaches for New Materials Discovery 2003年2月19日

  75. Combinatorial exploration of transparent ferromagnetism in transition metal doped wide gap oxide semiconductors 国際会議

    19<SUP>th</SUP> General Conference of the EPS Condensed Matter Division held jointly with CMMP 2002年4月7日

  76. Development of combinatorial PLD-STM system for quick nano-fabrication and evaluation 国際会議

    MRS Fall Meeting 2001年11月26日

  77. Combinatorial discovery of transparent ferromagnetsim in transition metal doped TiO<SUB>2</SUB> 国際会議

    The 2<SUP>nd</SUP> Int'l WS on Novel Quantum Phenomena in Transition metal oxides 2001年8月23日

  78. Parallel synthesis and high throughput characterization of ZnO based alloy films,heerostructures and devices 国際会議

    M.Kawasaki

    10<SUP>th</SUP> Int'l Conf. On Modulated Semiconductor Structures 2001年7月23日

  79. Combinatorial synthesis and high-throughput evaluation of doped TiO<SUB>2</SUB> thin films for the development of photocatalysis 国際会議

    SPIE Symposium 2000年1月22日

  80. Combinatorial Laser MBE for Oxide Alloy and Lattice Engineering 国際会議

    APS March Meeting 1999年3月23日

  81. パワー半導体SiC 薄膜のVLS 成長とその関連技術 招待有り

    松本 祐司

    (公財)科学技術交流財団 第1回「厳環境下IoT ワイドギャップ素子研究会」 2021年6月4日

︎全件表示 ︎最初の5件までを表示

産業財産権 1

  1. 有機化合物析出方法及びその装置

    松本 祐司, 榎本 大貴, 西ヶ花 完

    産業財産権の種類: 特許権

共同研究・競争的資金等の研究課題 22

  1. 組成変調ナノエンジニアリング:酸化物混晶・複合薄膜の新物性・機能開拓

    松本 祐司

    提供機関:Japan Society for the Promotion of Science

    制度名:Grants-in-Aid for Scientific Research

    研究種目:Grant-in-Aid for Scientific Research (B)

    研究機関:Tohoku University

    2020年4月1日 ~ 2023年3月31日

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    計画1 光触媒材料への応用 (電子・光)「MgZnOのバンドギャップ/分極傾斜膜と光励起キャリア寿命」昨年度の結果をもとに,人工的に導入したバンドギャップ傾斜構造が光電気化学特性に与える影響を検討した。 その結果,光CV曲線測定では,ダウングレード膜の方がアップグレード膜よりも光アノード電流密度が有意に増強され,さらに,光酸化能の観点からは,AgNO3水溶液を用いた光反応実験において,ダウングレード膜の方がアップグレード膜よりも多くの銀酸化物を生成することが確認された。 計画2 磁性材料への応用(磁気)「傾斜組成La1-xSrxMnO3薄膜の作製と磁気相図と磁気抵抗効果」LSAT(001)基板上に作製したLa0.7Sr0.3MnO3(LSMO)膜に4dのRuを添加すると磁気異方性が変化するとの報告から,Ru添加濃度が傾斜したRu:LSMO膜を作製し,SIMS測定からその組成傾斜構造を確認した。 計画4 電極材料開発への応用(イオン)「LiCoO2-LiNiO2傾斜組成膜の作製とLi拡散」昨年度に引き続き,STO(001)基板上でLi1.4Ni2/3Mn1/3O2(NM) とLi1.4Ni1/3Mn1/3Co1/3O2(NMC)の単膜作製条件の最適化とそのCo傾斜組成膜を作製した。 XRDによるCoの濃度変化に対するc軸長変化が既往の報告結果と概ね一致することで,堆積条件の最適化を確認した。この結果に基 づき,Co組成が膜厚方向に増大した傾斜組成薄膜を試作した。その結果,XRD測定によるピークのブロードニングから組成が傾斜してい ることが示唆された。

  2. 遷移金属酸化物のエピタキシーと電子相解析による電極活物質の開発

    大友 明, 松本 祐司, 組頭 広志, 吉松 公平, 増子 尚徳, 中村 研太郎, 黒川 輝, 相馬 拓人

    提供機関:Japan Society for the Promotion of Science

    制度名:Grants-in-Aid for Scientific Research

    研究種目:Grant-in-Aid for Scientific Research (B)

    研究機関:Tokyo Institute of Technology

    2015年4月1日 ~ 2018年3月31日

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    遷移金属酸化物は,無毒性や化学的安定性のため,種々の電気化学セルに利用されている。本研究では,薄膜技術と電子相図を用いた解析手法とを組み合わせて,遷移金属酸化物の新しい電気化学的機能を見出すことを目的とした.主な研究成果は以下の通りである.(1)鉄系薄膜からなる光電極構造を様々に工夫した結果,水の光電気化学分解反応の効率が大幅に向上した.(2)チタン酸リチウム薄膜の完全かつ可逆的な超伝導体-絶縁体転移をリチウムイオンの電気化学ドーピングにより実現した.(3)酸化チタン薄膜における新しい超伝導相を発見した.我々の研究方法は,持続可能な社会の構築に役立つ新材料・新機能を見つける強力な方法といえる.

  3. ナノ相分離強誘電体薄膜のナノ界面応力と分極自由回転現象の起源

    松本 祐司, 丸山 伸伍

    提供機関:Japan Society for the Promotion of Science

    制度名:Grants-in-Aid for Scientific Research

    研究種目:Grant-in-Aid for Scientific Research (A)

    研究機関:Tohoku University

    2015年4月1日 ~ 2018年3月31日

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    Bi層状ペロブスカイト強誘電体とスピネルフェライトナノ相分離薄膜における強誘電体相の成長温度に依存した超格子構造を明らかにするとともに、界面での応力効果を計算により見積もった。また、分極軸成分が面直方向となる配向の異なるナノ相分離膜を作製し、その分極反転特性を調査した。高効率な多元成分薄膜のPLD合成に、ガルバノ走査型PLD装置を新たに開発し、組成が膜成長方向にナノレベルで傾斜したBaTiO3-Ba0.7Sr0.3TiO3傾斜組成膜を作製し、PFMにより、分極反転に必要な電界強度を測定した結果、理論的に予測されているような薄膜中に内部電界が発生していることが示唆された。

  4. 規整ナノ反応場の構築と新しい触媒機能の創出

    高草木 達, 原 賢二, 清水 研一, 松本 祐司, 瀧川 一学

    提供機関:Japan Society for the Promotion of Science

    制度名:Grants-in-Aid for Scientific Research

    研究種目:Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)

    研究機関:Hokkaido University

    2013年6月28日 ~ 2018年3月31日

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    本研究では、表面金属ナノクラスター触媒(酸化物担持金属触媒)と固定化金属錯体触媒を用いた環境浄化及びグリーン有機合成反応をターゲットとし、単結晶モデル表面を始めとした規整ナノ反応場の原子レベル構造評価と実触媒の開発を並行して行った。担持金属触媒では、特に金属/酸化物界面に形成される特異なナノ構造による分子活性化に着目し、固定化金属錯体触媒では錯体の空間的配列や配向などの局所構造が触媒活性に与える影響を検討した。また、情報学的手法を用いた新規触媒物質の高速かつ高精度探索法の開拓を行った。

  5. イオン液体を用いた昇華-再結晶ハイブリッド型有機材料精製プロセスの開発

    松本 祐司

    提供機関:Japan Society for the Promotion of Science

    制度名:Grants-in-Aid for Scientific Research

    研究種目:Grant-in-Aid for Challenging Exploratory Research

    研究機関:Tohoku University

    2013年4月1日 ~ 2015年3月31日

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    本研究では、新規に高効率な有機材料の精製プロセス開発を目的に、昇華-再結晶ハイブリッド型精製炉を試作し、これを検証した。本装置を用いて、減圧された加熱容器中で、Arガスフローの下、ペンタセンを固体から直接蒸発(昇華)させ、その蒸気成分を含むArガスを、不揮発性のイオン液体に通ずることで、ペンタセンをイオン液体中で析出結晶(再結晶)化させることに成功した。このプロセスでは、昇華と再結晶の2つの効果で効率よく有機材料が精製されることが期待され、予備実験から、不純物であるペンタセンキノンが効率よく除去されることが示された。

  6. 金属ガラスフラックスを介したSiC単結晶の気相成長法の開発

    松本 祐司

    提供機関:Japan Society for the Promotion of Science

    制度名:Grants-in-Aid for Scientific Research

    研究種目:Grant-in-Aid for Challenging Exploratory Research

    研究機関:Tokyo Institute of Technology

    2011年 ~ 2012年

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    本研究では、金属ガラスフラックス(融液)探索のためのレーザー加熱型の真空レーザー顕微鏡の開発を行い、SEMのその場観察の結果と併せて、金属ガラスのSiC単結晶上での溶解と偏析過程を明らかにした。また、Si-Niフラックスを用いて、フラックス成長を試みたところ、結晶グレインサイズの大幅な拡大と表面平坦化が達成され、高品質化を目的としたSiC薄膜成長におけるフラックス気相成長法の有効性が実証された。

  7. イオン液体を介したイオン性固体結晶の真空製膜法の開発

    松本 祐司

    2009年 ~ 2010年

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    本研究課題では、研究代表者がこれまで開発に従事してきた真空下で安定に存在する液体フラックスを用いた真空製膜法であるフラックスエヒタキシー法を酸化物薄膜ばかりでなく、アルカリハライド固体材料に応用するため、以下の研究内容を通じて,イオン液体を介したエヒタキシャルアルカリハライド薄膜の新フロセスの確立を目的としている。平成22年度は以下の研究項目を実施した。 (イオン液体を介したKBr(111)薄膜の作製) イオン液体を予め蒸着したサファイア基板上にKBrを赤外レーザーで蒸着した。サファイアの基板方位によらず、室温では、逆に結晶成長が阻害される傾向にあったが、基板温度を上げると、結晶性がよくなることがわかった。また、AFM観察から、c面サファイア基板上では、イオン液体を介すことで、KBr(111)面がよりよく成長し、かつ極性面による不安定性にもかかわらず、(111)面がnanoレベルで平坦化されたエヒタキシャルKBr結晶が得られることがわかった。KBrの成長後、試料をUHV-レーザー顕微鏡に移し、顕微鏡で観察しながら、真空中で加熱したところ、300℃付近で完全にイオン液体のみが蒸発し、KBr微結晶の輪郭がはっきりする様子を確認した。イオン液体除去後の試料の再度AFM観察を行ったところ、加熱したにもかかわらず、(100)面のファセットは生じず、安定な(111)面が保持されているのを確認した。以上の結果から、イオン液体を介することで、これまで困難であった、ナノレベルで平坦な(111)面を持つアルカリハライドエヒタキシャル薄膜の作製が可能であることが明らかになった。本成果は、ACSのCryst.&Growth Des.で発表するとともに、掲載号の表紙にもなった。

  8. エピタキシャル二酸化チタンヘテロ電極の光電気化学

    松本 祐司

    提供機関:Japan Society for the Promotion of Science

    制度名:Grants-in-Aid for Scientific Research

    研究種目:Grant-in-Aid for Scientific Research (B)

    研究機関:Tokyo Institute of Technology

    2008年 ~ 2010年

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    本研究では、TiO_2とその関連材料の単結晶・エピタキシャル薄膜を用いた光電気化学研究を通じて、以下の成果を得た。 (1)TiO_2の誘電率が電界に依存することを初めて明らかにした。 (2)パルスレーザ堆積装置と電気化学システムが複合化した新装置を開発し、電気化学的手法によるTiO_2薄膜中の酸素欠損分布のその場定量評価に成功した。 (3)TiO_2中のVが還元サイトとして、銀の光析出反応を促進することを明らかにした。 (4)Nbを高濃度に添加したSrTiO3とTiO_2の光酸化作用を利用して、クラスレート型の銀酸化物の合成に成功した。

  9. 強相関相転移現象の表面化学と電界効果化学反応デバイスの開発

    松本 祐司

    2005年 ~ 2007年

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    本研究提案では、基礎と応用の観点から以下の2つを主な目的とする。 (1)強相関電子系に特有な電子状態の劇的な相転移現象の表面に与える影響を触媒反応のような化学的なアプローチで、STMを用いて原子レベルでこれを検証する。 (2)強相関電子系に特有の劇的な相転移現象を電界で制御し、その効果を最大限にチューニングすることで、表面での吸着や化学反応と組み合わせた超高感度化学センサーの原理証明を行う。 【研究成果1】超高真空温度可変高分解能STM-PLDシステムの開発本年度は、前年度に設計・開発したレーザー加熱型のPLD装置の立ち上げに、二酸化チタンアナターゼ薄膜、およびその表面上のCr担持構造の再現実験を行った。作製した二酸化チタン薄膜の原子像こそまだ得られていないが、ステップ-テラス構造をSTM観察することができた。また、in situでのLEED/AES解析と組み合わせ、Cr担持アナターゼ表面構造の形成機構に関する新しい知見を得ることができた。 【研究成果2】強相関系ハーフメタル材料Sr_2FeMoO_6薄膜の作製今後、温度可変のSTM観察で相転移温度が300〜400K付近である興味ある材料の1つとして、Sr_2FeMoO_6薄膜の作製を試みた。FeとNoの組成比を制御することで、バルク単結晶に匹敵するハーフメタル磁気特性を有する薄膜の作製に成功した。また、Fe/Mo比を変化させることで、相転移温度を制御できることがわかったので、STM観察に適した試料作製の指針を得ることができた。

  10. ナノテクノロジーを用いた深紫外半導体発光デバイスの開発とその応用

    青柳 克信, 武内 道一, 井上 振一郎, 平山 秀樹, 松本 祐司, 鯉沼 秀臣, 前田 瑞夫, 川崎 宏治, 荒川 泰彦

    提供機関:Japan Society for the Promotion of Science

    制度名:Grants-in-Aid for Scientific Research

    研究種目:Grant-in-Aid for Creative Scientific Research

    2003年 ~ 2007年

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    本研究では現在問題となっている環境問題を抜本的に解決することができる超高出力固体深紫外発光素子を開発するための新たな提案とその原理実証研究を行い、又そのために必要な結晶成長機構の解明、p型高ドーピング手法の開発並びに高効率非線形光学素子の開発を行った。その結果、1.深紫外発光のためのAlGaN半導体エピタキシャル結晶成長で新たに2光束その場観測法を開発し、今まで全く不明であった成長過程をつぶさに観測することに成功し、経験によっていた結晶成長を科学的に解明することで、高品質結晶を再現性よく作ることに成功した。2.今まで不可能であった280nmで発光する縦型深紫外電流注入発光デバイス(LED)を作製することに成功し、スケール則により従来不可能と考えられていた超高出力の深紫外LEDの実現に大きなマイルストーンを築いた。3.又量子ドットを用いたAlGaInN系材料で335nmの発光に成功した4.本研究により新たなヘテロ非線形フォトニック結晶の概念を打ち出しそれを作り出すことに成功し、通常の300倍以上の高い非線形性を得ることに成功した。その結果He-Cdレーザーに取って代わる深紫外レーザー(325nm)を実現することに成功した。又これによってHe-Cdレーザーに取って代わる全固体深紫外レーザーへの道を開いた。5.新たなボロン系酸化物(RECa_40(BO_3)_3RECOB)の非線形材料を作ることに独自のフラックス結晶成長法で成功しこれを用いた深紫外発光導波型デバイスへの道を開いた。6.温度変調法並びにコンビナトリアル手法を用いZnOでのp型の高濃度ドーピングに成功し、将来の紫外ZnO高出力発光素子の道を開いた。これらの結果は55編の原書論文、8件の招待講演を含む55件の国際会議並びに7件の招待講演を含む79編の国内会議で発表され、13件の特許として成果が示されている。

  11. 二酸化チタン電界効果トランジスターの開発

    松本 祐司

    2005年 ~ 2006年

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    【研究目標】 二酸化チタンの電子デバイスとしての新機能探索を目的として、 1)ルチル単結晶を用いた電界効果トランジスタを試作し、原理的に動作することを検証する。 2)ルチル、アナターゼエピタキシャル薄膜を用いた電界効果トランジスタを試作し、特性の最適化を行い、実用化の必須条件である移動度が1cm^2/Vsを越えるデバイスを作る。 以上、2つのことを本研究課題の目標とする。 【研究成果1】アナターゼ型二酸化チタン電界効果トランジスタの動作実証 高品質のアナターゼエピタキシャル薄膜をLaA103(001)単結晶基板上に作製し、トップゲート型のトランジスタを試作した。アナターゼ薄膜作製時に、「酸素変調法」という断続的な薄膜堆積と高酸素圧処理とを組み合わせることで、高い結晶性と絶縁性を確保し、on/off比10^5、電界効果移動度0.37cm2/Vsを達成した。 【研究成果2】真空グローバーシステムを用いたボトムゲート型二酸化チタンTFTの低温測定とガス感度特性 本研究費により、購入した真空グローバーシステムを用いて、100KでのTFT特性を評価した。通常、低温にすると移動度が増大するが、今回作製したTFTでは、顕著な意同度の増大は観測されなかった。絶縁層とチャネル層との界面特性を向上する必要があるものと考えられる。また、ボトムゲート型のTFTにおいては、光照射効果と併せて、酸素雰囲気によるTFT特性の変化を調べた。その結果、ゲート電極を適当に調節することで、ガスセンサーとして機能する可能性を見いだした。

  12. フラックスエピタキシー法による高機能性単結晶基板の開発

    鯉沼 秀臣, 松本 祐司, 宮澤 信太郎

    提供機関:Japan Society for the Promotion of Science

    制度名:Grants-in-Aid for Scientific Research

    研究種目:Grant-in-Aid for Scientific Research (B)

    2004年 ~ 2005年

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    【研究目標】 我々は、フラックスエピタキシーという新しい方法を提案し、本手法を用いた高機能性単結晶基板製造プロセスを確立することを目的とする。単結晶でかつ原子レベルで平坦な表面を有するGaNや酸化亜鉛薄膜成長用基板や光学デバイス用、高温超伝導薄膜用SrTiO_3基板を作成し、機能デバイス用基板としての工業化を追求する。 【研究成果】 1,MgO(001)単結晶基板上のBi-cu-Oフラックスのレーザー顕微鏡その場観察 MgO(001)単結晶基板上のBi-cu-Oフラックスのレーザー顕微鏡その場観察し、真空下と大気圧下での液'滴挙動の比較検討を行った。その結果、液滴の合体挙動の液化温度は、大気下の方が高いが、その合体頻度は大きく、活性化エネルギーに明らかな違いが見いだされた。 2,ZnO単結晶の表面処理技術の検討 高温・真空下で安定なBi-Cu-Oフラックスを用いた単結晶酸化物表面の処理法について検討を行った。X線回折法によるマクロな領域ではフラックス処理による表面のラフニング、結晶性の一見の低下が確認されたが、RBS測定による原子の格子位置からのズレというミクロな加工歪の観点からは、フラックス処理に拠って改善されることが示唆された。 3,フラックス固相エピタキシーによるScMgAlO_4(SCAM)薄膜の実現 同様に、高温・真空下で安定なBi-Cu-Oフラックスを用いたZnO薄膜用基板として知られるSCAM薄膜の作製を行った。サファイア基板上にアモルファス状のフラックスと原料成分を堆積し、電気炉で焼成すると、SCAM薄膜が成長することを世界で初めて見いだした(特許申請済)。

  13. 真空成膜法による新機能スピントロニクス材料の探索

    松本 祐司

    提供機関:Japan Society for the Promotion of Science

    制度名:Grants-in-Aid for Scientific Research

    研究種目:Grant-in-Aid for Scientific Research on Priority Areas

    研究機関:Materials and Structures Laboratory

    2002年 ~ 2005年

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    【研究目標】 1回の実験で多種類の試料を合成・評価することができるコンビナトリアル分子線エピタキシー法を用いて、酸化物薄膜をベースとした新しいスピントロニクス機能を有する材料の高速探索と物性評価を行う。原子層レベルで制御されたエピタキシー技術により、酸化物磁性超格子やナノ構造をデザインし、構造と磁気物性との関係を高速、かつ系統的に調べる。 【研究成果1】Co : TiO_2室温透明磁性半導体のメカニズムと応用展開 X線MCDにより、Co2+状態が強磁性の起原であることを実証するとともに、XANES/EXAFSなどの手法により、ミクロな構造について調べた。また、平坦化二酸化チタン単結晶基板を用いた低温成長法を開発し、Co : TiO_2の高品質化を達成した。電界効果による磁性制御を目指した、Co : TiO_2をチャネル層とする電界効果トランジスターを試作した。また、Co : TiO_2と還元されたTiO_2層との交互積層構造を作製し、効率良くキャリアを注入する方法を提案し、それを検証した。 【研究成果2】世界初磁性超伝導Ru1222エピタキシャル薄膜の実現と磁気異方性 強磁性と超伝導が共存することで知られるRu1222化合物のエピタキシャル薄膜をCuOをフラックスとして用いたFlux-assisted RSE法により、世界で初めて実現した。これにより、本化合物の結晶構造に由来する大きな磁気異方性を初めて実験的に示すことができた。

  14. スピントロニクス物性研究調整班

    勝本 信吾, 藤森 淳, 瀧田 宏樹, 松本 祐司, 吉野 淳二

    2002年 ~ 2005年

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    勝本グループでは,量子ドットの近藤状態が,特定の干渉計の中で干渉を生じる際に起こるFano近藤効果を,T結合型の量子ドットおよびABリング中に量子ドットを埋め込んだ系において観測した.ABリングの系においては,磁場によって干渉パラメーターを変化させて,あらゆるパラメーターの領域でπ/2へのロックが生じていることを確認した.また,(Ga,Mn)AsからのTHz発光を発見した. 松本グループでは酸素圧変調方式を用いてCo:TiO2/TiO2人工格子の界面キャリア注入に成功し,これをXMCDで確認した. 瀧田グループでは,(Zn,Cr)Teにおけるドーピング効果を明らかにし,室温強磁性発現に成功すると共に,そのメカニズムについても重要な知見を得た. 藤森グループでは,XMCDの手法を駆使し,本調整班他グループとの共同研究で,これまで疑問とされてきた,Co:TiO2やCo:ZnO,また(Ga,Mn)Nの磁性が間違いなく希薄磁性であることを証明した. 吉野グループでは,(Ga,Mn)Asの2重障壁構造において電流注入による磁化反転を試み,記録的な低電流閾値での磁化反転に成功した.

  15. トライフェーズエピタキシー法による酸化物単結晶薄膜の作製と新機能開発

    鯉沼 秀臣, 長谷川 哲也, 知京 豊裕, 松本 祐司, 伊高 健治

    提供機関:Japan Society for the Promotion of Science

    制度名:Grants-in-Aid for Scientific Research

    研究種目:Grant-in-Aid for Scientific Research (B)

    研究機関:Tokyo Institute of Technology

    2002年 ~ 2003年

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    トライフェーズエピタキシー(TPE)法はバルク単結晶を作製する方法の一つであるフラックス法に基づいた薄膜作製技術である。フラックス成分をあらかじめ基板上に堆積し、基板を高温まで加熱することで液状化したフラックス層を介して薄膜を堆積させる。この手法によって高温超伝導体NdBa_2Cu_3O_<7-d>(Nd123)の単結晶薄膜の作製に成功し、TPE手法の有効性を実証してきた。H14年度では、このTPE手法を、CaをドープしたNd123、強誘電体(Bi_4Ti_3O_<12>)の薄膜作製への適用を試みるとともに、3成分系のコンビナトリアル合成システムを新たに開発し、実験の高効率化を図った。 H15年度では、前年度に開発した技術をもとにコンビナトリアル手法を用いた強誘電体(Bi_4Ti_3O_<12>)の新規フラックス材料の探索を試みた。コンビナトリアル探索の結果、Bi-Cu-Oという新しいフラックス材料を見出すことに成功した。このフラックス材料を使用することで基板のステップ構造に起因する転位の発生や蒸気圧の高いBi酸化物の蒸発を抑制し、強誘電体Bi_4Ti_3I_<12>の単結晶薄膜実現した。さらにTPE手法を固相プロセスへ応用したフラックス固相エピタキシーの概念を提案した。フラックス材料を使用しない一般的な手法によって強誘電体Bi_4Ti_3O_<12>の薄膜を作製し、その上にフラックスとなるBi_2O_3を堆積させ、真空中にて高温アニールを行った。アニール前は小さなグレインが存在し荒れていた表面が、分子層ステップを有する平坦な表面までに改善された。TPE手法は気相プロセスだけでなく、フラックス固相エピタキシーとして固相プロセスにも応用できることが本実験から示された。

  16. レーザーMBE法による、TiO_2薄膜の作成とその電気化学的光特性の評価

    松本 祐司, 大森 隆

    1999年 ~ 1999年

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    1)基板の整合性などを利用して、熱力学的安定性の異なるアナターゼ/ルチルの2種の結晶構造をレーザMBE法を用いて制御することに成功した。基板としてl12O3(0001)基板を用いると、ルチル型結晶(TiO2(R))の(100)が、SrTiO3(001)(STO)基板を用いるとアナターゼ型結晶(TiO2(A))の(001)が広い成膜温度範囲で単相として得られることを見い出した。さらに、窒化チタンの酸化過程を用いた、TiN(001)/TiO2(A)/STOエピタキシャル多層膜の高温酸化処理により、通常の熱力学的支配のもとでは達成できない、良質なしかもエピタキシャル関係を保ったTiO2(R)/TiO2(A)/STOの多層構造の作成に成功した。 2)コンビナトリアルケミストリーの手法を取り入れたコンビナトリアルレーザMBE装置を用いて、アナターゼ/ルチルのそれぞれの結晶に系統的に遷移金属をドープした。その結果、ルチル型のバルクで20%以上固溶すると報告されているV、Feに対して、アナターゼ型ではルチルに比べて溶けにくいこと、また、それとは逆にルチル型のバルクでは、固溶しないCoについては、アナターゼ型で良く溶けることなど、非常に興味深い結果が得られた。 3)電気化学触媒反応の評価を視覚的にかつ高速に評価できる装置を企業と共同開発し、特許申請を行った。Si-SiO2-Si3N4の多層膜からなるセンサーにレーザを照射して誘起される光電流の強度が、局所的な水素イオン濃度に依存することを利用した、pHイメージング法を用いた。Fe2(SO4)3などの酸化もしくはKIなどの還元試薬を用いて、TiO2薄膜上で光水分解後のpH変化を調べた結果、それぞれの薄膜ライブラリーでのpH変化の違いが確認され、この手法がコンビナトリアルに合成された光触媒の高速活性評価に適用できる可能性が示された。

  17. コンビナトリアル手法による、新機能性材料・デバイス探索 競争的資金

  18. Atomic level control of surface-interface structure and property 競争的資金

  19. Transparent magnet of TiO2 and its application to spin electronics 競争的資金

  20. 表面・界面の構造と物性の原子レベル制御 競争的資金

  21. 二酸化チタン透明磁石の開発とスピンエレクトロニクスへの応用 競争的資金

  22. Combinatorial exploration of new functional materials and devices 競争的資金

︎全件表示 ︎最初の5件までを表示

Works(作品等) 1

  1. コンビナトリアル技術を用いた新型触媒等の新材料開発

    2002年 ~ 2002年

    作品分類: 芸術活動