Updated on 2025/12/17

写真a

 
KUWANO TARO
 
Organization
School of Materials and Chemical Technology Assistant Professor
Title
Assistant Professor
External link

Degree

  • Ph.D (Engineering) ( 2022.3   Kyoto University )

Research Interests

  • Semiconductors, Dielectrics, Phosphides, Oxides, titanite, antiferroelectrics, DIelectric breakdown

Research Areas

  • Nanotechnology/Materials / Inorganic materials and properties  / Semiconductors, Dielectrics, Phosphides, Oxides

Education

  • Kyoto University   Graduate School of Engineering   Deprtment of Materical Science and Engineering

    2019.4 - 2022.3

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    Country: Japan

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  • Kyoto University   Graduate School of Engineering   Deprtment of Materical Science and Engineering

    2017.4 - 2019.3

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    Country: Japan

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  • Kyoto University   Faculty of Engineering   School of Engineering Science

    2013.4 - 2017.3

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    Country: Japan

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Research History

  • Institute of Science Tokyo   Department of Materials Science and Engineering   Assistant Professor

    2024.10

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    Country:Japan

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  • Tokyo Institute of Technology   Department of Materials Science and Engineering   Assistant Professor

    2024.4 - 2024.9

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    Country:Japan

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  • Nagoya University   Graduate School of Science   Project assistant professor

    2022.4 - 2024.3

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    Country:Japan

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  • JSPS research fellow (DC2)

    2021.4 - 2022.3

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    Country:Japan

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  • National Renewable Energy Laboratory   Guest researcher

    2019.11 - 2020.3

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    Country:United States

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Professional Memberships

  • The Creamics Society of Japan

    2023.1

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  • The Physical Society of Japan

    2022.6

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  • The Japan Society of Applied Physics

    2017.4 - 2022.3

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Committee Memberships

  • The Physical Society of Japan   Division 10 Committee Member(Dielectrics sub-division)  

    2024.10 - 2025.9   

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    Committee type:Academic society

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Papers

  • Thermally stable dielectric and structural properties of titanite-type SrZrGeO5

    Taro Kuwano, Hiroko Yokota, Manabu Hagiwara, Toshiya Uohashi, Akitoshi Nakano, Kazuhiko Deguchi, Hiroki Taniguchi

    Ceramics International   2025.12

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.1016/j.ceramint.2025.11.056

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  • Phase variety of titanite-type solid solutions (Ca, Pb)TiGeO5: paraelectric and antiferroelectric states in monoclinic and triclinic lattices Reviewed International journal

    Zerui Li, Taro Kuwano, Hiroko Yokota, Shintaro Yasui, Manabu Hagiwara, Toshiya Uohashi, Akitoshi Nakano, Hiroki Taniguchi

    Japanese Journal of Applied Physics   2025.8

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.35848/1347-4065/adf2b4

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  • Titanite-type solid solutions (Ca,Pb)TiGeO5: A competition between triclinic and antiferroelectric distortions Reviewed International journal

    Zerui Li, Taro Kuwano, Akitoshi Nakano, Manabu Hagiwara, Shintaro Yasui, Hiroki Taniguchi, Hiroko Yokota

    Journal of the Ceramic Society of Japan   133 ( 7 )   275 - 280   2025.7

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    Authorship:Corresponding author   Language:English   Publishing type:Research paper (scientific journal)   Publisher:Ceramic Society of Japan  

    DOI: 10.2109/jcersj2.25007

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  • Improving the dielectric temperature stability of Bi2SiO5-based ceramics through the spontaneous formation of paraelectric–ferroelectric nanocomposite structures Reviewed International journal

    Yoji Yasumoto, Taro Kuwano, Hiroki Taniguchi, Shinobu Fujihara, Manabu Hagiwara

    Dalton Transactions   2025

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1039/D5DT01380A

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  • High dielectric breakdown strength of antipolar CaTiGeO5 ceramics sintered at optimized temperature Reviewed International journal

    Manabu Hagiwara, Taro Kuwano, Hiroki Taniguchi, Shinobu Fujihara

    Ceramics International   50 ( 18 )   34197 - 34204   2024.9

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Elsevier BV  

    DOI: 10.1016/j.ceramint.2024.06.239

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  • Effect of Al–Nb codoping on dielectric properties and breakdown strength of rutile TiO2 ceramics Reviewed International journal

    Mitsuha Kawasaki, Taro Kuwano, Hiroki Taniguchi, Shinobu Fujihara, Manabu Hagiwara

    Journal of the Ceramic Society of Japan   132 ( 7 )   304 - 311   2024.7

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Ceramic Society of Japan  

    DOI: 10.2109/jcersj2.23212

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  • Unconventional Polarization Response in Titanite-Type Oxides due to Hashed Antiferroelectric Domains Reviewed International journal

    Hiroki Taniguchi, Takumi Watanabe, Taro Kuwano, Akitoshi Nakano, Yukio Sato, Manabu Hagiwara, Hiroko Yokota, Kazuhiko Deguchi

    ACS Nano   2024.5

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:American Chemical Society (ACS)  

    DOI: 10.1021/acsnano.4c02168

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  • Antiferroelectricity of titanite-type oxide SrTiGeO5 and its potential for power electronics applications Reviewed International journal

    Toshiya Uohashi, Taro Kuwano, Manabu Hagiwara, Kenji Natori, Kazuhiko Deguchi, Hiroki Taniguchi

    Applied Physics Letters   124 ( 18 )   2024.4

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:AIP Publishing  

    Antiferroelectric materials have recently received renewed attention due to the increased demand for energy-storage ceramics and power electronics applications. This study demonstrates antiferroelectricity in a titanite-type oxide, SrTiGeO5, through direct observation of a double D-E hysteresis loop by polarization measurements. Temperature dependence of dielectric permittivity shows a cusp around 550 K, indicating a relatively high antiferroelectric phase transition temperature for SrTiGeO5. It is suggested that an electric-field-induced rise of permittivity in SrTiGeO5 has the potential for application in protective circuits of power electronics devices. The present study paves the way for the development of innovative antiferroelectric applications.

    DOI: 10.1063/5.0204239

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  • Re-estimation of Maxwell-Wagner relaxation for novel absorbers via (Ta+Ga)-doped rutile-type TiO2 ceramics with various valence proportions and sintering temperatures Reviewed International journal

    Taro Kuwano, Yujiro Hashimoto, Kazuhiko Deguchi, Hiroki Taniguchi

    Journal of Alloys and Compounds   966   171624 - 171624   2023.12

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    Authorship:Lead author, Corresponding author   Language:English   Publishing type:Research paper (scientific journal)   Publisher:Elsevier BV  

    DOI: 10.1016/j.jallcom.2023.171624

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  • Temperature-Stable Linear Dielectric Response of Low-Temperature Sintered La-Doped Bi2SiO5 Ceramics Reviewed International journal

    Yoji Yasumoto, Taro Kuwano, Hiroki Taniguchi, Shinobu Fujihara, Manabu Hagiwara

    ACS Applied Electronic Materials   2023.7

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:American Chemical Society (ACS)  

    DOI: 10.1021/acsaelm.3c00586

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  • Controlling dielectric properties of Nb + X (X = Al, Ga, In) co-doped and Nb-doped rutile-type TiO2 single crystals Reviewed International journal

    Shota Kakimoto, Yujiro Hashimoto, Taro Kuwano, Koji Kimura, Kouichi Hayashi, Manabu Hagiwara, Kazuhiko Deguchi, Hiroki Taniguchi

    Journal of Materials Chemistry C   11 ( 4 )   1304 - 1310   2023

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Royal Society of Chemistry (RSC)  

    Dielectric properties of Nb-doped TiO2 single crystals measured before and after the special post-annealing with Ga2O3 embedding powder, shedding light on local structure engineering for permittivity boosting in dielectric materials.

    DOI: 10.1039/d2tc03914a

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  • Deep level transient spectroscopy and photoluminescence studies of hole and electron traps in ZnSnP2 bulk crystals Reviewed International coauthorship International journal

    Taro Kuwano, Ryoji Katsube, Steve Johnston, Adele C. Tamboli, Yoshitaro Nose

    Japanese Journal of Applied Physics   61 ( 2 )   020905 - 020905   2022.2

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.35848/1347-4065/ac468a

    Web of Science

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  • Performance enhancement of ZnSnP2 solar cells by a Cu3P back buffer layer Reviewed International journal

    Taro Kuwano, Ryoji Katsube, Kenji Kazumi, Yoshitaro Nose

    SOLAR ENERGY MATERIALS AND SOLAR CELLS   221   2021.3

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    Authorship:Lead author   Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1016/j.solmat.2020.110891

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  • Improvement of Ohmic Behavior of Back Contact in ZnSnP2 Solar Cells by Inserting Cu3P Reviewed International journal

    Taro Kuwano, Ryoji Katsube, Yoshitaro Nose

    2019 IEEE 46TH PHOTOVOLTAIC SPECIALISTS CONFERENCE (PVSC)   3007 - 3009   2019

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    Authorship:Lead author   Language:English   Publishing type:Research paper (international conference proceedings)  

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  • Impact of structure on carrier transport behavior at the interface between electrode and ZnSnP2 absorber Reviewed International journal

    Taro Kuwano, Shigeru Nakatsuka, Yoshitaro Nose

    2018 IEEE 7TH WORLD CONFERENCE ON PHOTOVOLTAIC ENERGY CONVERSION (WCPEC) (A JOINT CONFERENCE OF 45TH IEEE PVSC, 28TH PVSEC & 34TH EU PVSEC)   2998 - 2999   2018

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    Authorship:Lead author   Language:English   Publishing type:Research paper (international conference proceedings)  

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MISC

  • Fabrication process and device application of chalcopyrite phosphides based on thermodynamics

    Nose Yoshitaro, Katsube Ryoji, Kuwano Taro

    JSAP Review   2022 ( 5 )   n/a   2022

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    Language:English   Publisher:The Japan Society of Applied Physics  

    In this article, we introduce our studies on the application of chalcopyrite phosphides to solar cells, including bulk crystal growth based on the phase diagram, and thin film deposition through chemical potential diagram. A phase diagram is a useful tool for the fabrication of multi-component materials, while the chemical potential diagram, which is a kind of phase diagram with chemical potentials as axes, is well suited for discussing vapor growth. As another example of using the chemical potential diagram, the stability of a hetero-interface is presented. In addition, bandgap control through order-disorder phenomena is described.

    DOI: 10.11470/jsaprev.220411

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Presentations

  • チタン石型酸化物固溶体(Ca,Pb)TiGeO5の相転移

    桑野 太郎, 李 澤瑞, 横田 紘子, 安井 伸太郎, 萩原 学, 魚橋 毅也, 中埜 彰俊, 谷口 博基

    第42回強誘電体会議  2025.6 

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    Event date: 2025.6

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

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  • Role of aluminum source in solid-state reaction of titanite-type oxide CaTaAlO5

    Ichinari Endo, Taro Kuwano, Hiroko Yokota, Shintaro Yasui, Manabu Hagiwara, Hiroki Taniguchi

    2025.3 

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    Event date: 2025.3

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  • Low-temperature dielectric properties of titanite-type solid solutions (Ca,Pb)TiGeO5

    Zerui Li, Taro Kuwano, Hiroko Yokota, Shintaro Yasui, Manabu Hagiwara, Toshiya Uohashi, Akitoshi Nakano, Hiroki Taniguchi

    2025.3 

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    Event date: 2025.3

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    Country:Japan  

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  • 新規チタン石型酸化物PbTiGeO5の誘電特性と固溶体の作製

    Li Zeui, 桑野太郎, 萩原学, 安井伸太郎, 谷口博基, 横田紘子

    第44回電子材料研究討論会  2024.11 

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    Event date: 2024.11

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  • Synthesis and Dielectric Properties of Lead-including Titanite-type Oxide PbTiGeO5 International conference

    Zerui Li, Taro Kuwano, Shintaro Yasui, Hiroki Taniguchi, Hiroko Yokota

    2024 US-Japan Seminar on Dielectric and Piezoelectric Ceramics  2024.11 

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    Event date: 2024.11

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  • Synthesis and dielectric property of a novel titanite-type oxide PbTiGeO5 International conference

    Zerui Li, Taro Kuwano, Shintaro Yasui, Hiroki Taniguchi, Hiroko Yokota

    The Fourteenth International Conference on the Science and Technology for Advanced Ceramics  2024.10 

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    Event date: 2024.10

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  • Structural and dielectric properties of titanite-type oxide Sr(Ti1-xSnx)GeO5

    Misaki Uemura, Taro Kuwano, Hiroki Taniguchi, Hiroko Yokota

    2024.9 

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    Event date: 2024.9

    Language:Japanese   Presentation type:Poster presentation  

    Country:Japan  

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  • Synthesis of PbTiGeO5 titanite at low temperature International conference

    Zerui Li, Taro Kuwano, Yokota Hiroko

    The 14th Japan-Korea Conference on Ferroelectrics  2024.9 

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    Event date: 2024.8 - 2024.9

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  • Dopant distribution in rutile-type TiO2 doped with aliovalent cations Invited International conference

    Taro Kuwano

    The 16th Japan-China Symposium on Ferroelectric Materials and Their Applications  2024.7 

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    Event date: 2024.7

    Language:English   Presentation type:Oral presentation (invited, special)  

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  • Synthesis of titanite-type Na(Nb,Ta)GeO5 solid solutions and investigation of their antiferroelectricity

    Taro Kuwano, Toshiya Uohashi, Manabu Hagiwara, Akitoshi Nakano, Kazuhiko Deguchi, Hiroki Taniguchi

    2024.6 

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    Event date: 2024.6

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  • Synthesis and antiferroelectricity of titanite-type oxide Na(Nb,Ta)GeO5

    T. Kuwano, A. Nakano, K. Deguchi, H. Taniguchi

    2024.3 

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    Event date: 2024.3

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  • Novel titanite-type oxide SrZrGeO5 and its solid solutions

    Taro Kuwano, Akitoshi Nakano, Kazuhiko Deguchi, Hiroki Taniguchi

    2024.3 

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    Event date: 2024.3

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  • Interface Structure and Carrier Transport Behavior between Cu Electrode and ZnSnP2 Absorber International conference

    Taro Kuwano, Shigeru Nakatsuka, Yoshitaro Nose

    International Symposium on Solar Energy Materials  2019.1 

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    Event date: 2019.1

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  • Mo/SLG界面およびMo薄膜におけるNaの挙動

    桑野太郎, 今宿晋, 野瀬嘉太郎

    第78回応用物理学会秋季学術講演会  2017.9 

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  • Effect of Interfacial Compounds between Back Electrode and Absorber on Performance of ZnSnP2 Solar Cells

    Taro Kuwano, Sigeru Nakatsuka, Yoshitaro Nose

    27th International Photovoltaic Science and Engineering Conference (PVSEC-27)  2017.11 

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  • SLGから拡散したMo薄膜中のNaの分布および化学状態

    桑野太郎, 今宿晋, 野瀬嘉太郎

    第65回応用物理学会春季学術講演会  2018.3 

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  • Impact of structure on carrier transport behavior at the interface between electrode and ZnSnP2 absorber

    Taro Kuwano, Sigeru Nakatsuka, Yoshitaro Nose

    2018 IEEE 7th World Conference on Photovoltaic Energy Conversion (WCPEC) (A Joint Conference of 45th IEEE PVSC, 28th PVSEC & 34th EU PVSEC)  2018.6 

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  • ZnSnP2吸収層とCu裏面電極との接合の界面構造とキャリア輸送

    桑野太郎, 勝部涼司, 野瀬嘉太郎

    第79回応用物理学会秋季学術講演会  2018.9 

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  • Improvement of Ohmic Behavior of Back Contact in ZnSnP2 Solar Cells by Inserting Cu3P International conference

    Taro Kuwano, Ryoji Katsube, Yoshitaro Nose

    46th IEEE Photovoltaic Specialists Conference (PVSC-46)  2019.6 

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    Country:United States  

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  • ZnSnP2太陽電池の裏面電極構造

    桑野太郎, 勝部涼司, 野瀬嘉太郎

    第16回「次世代の太陽光発電システム」シンポジウム  2019.7 

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    Country:Japan  

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  • ZnSnP2吸収層/Cu電極界面へのCu3Pの挿入による太陽電池の直列抵抗低減と変換効率向上

    桑野太郎, 勝部涼司, 野瀬嘉太郎

    第80回応用物理学会秋季学術講演会  2019.9 

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  • PLおよびDLTS 測定によるZnSnP2バルク結晶の欠陥評価 International coauthorship

    桑野太郎, 勝部涼司, Steve Johnston, Adele C. Tamboli, 野瀬嘉太郎

    第81回応用物理学会秋季学術講演会  2020.9 

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    Language:Japanese   Presentation type:Oral presentation (general)  

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  • Photoluminescence and Deep Transient Spectroscopy for ZnSnP2 Bulk Crystals International coauthorship International conference

    Taro Kuwano, Ryoji Katsube, Steve Johnston, Adele C. Tamboli, Yoshitaro Nose

    30th International Photovoltaic Science and Engineering Conference (PVSEC-30)  2020.11 

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  • ZnSnP2のMBE成長における基板温度の影響

    桑野太郎, 野瀬嘉太郎

    第82回応用物理学会秋季学術講演会  2021.9 

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  • Impact of substrate temperature on bandgap in ZnSnP2 thin films by MBE International conference

    Taro Kuwano, Yoshitaro Nose

    31st International Photovoltaic Science and Engineering Conference (PVSEC-31)  2021.12 

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  • 異価数元素共置換によるルチル型TiO2の誘電特性制御

    桑野太郎, 橋本友次郎, 出口和彦, 谷口博基

    日本物理学会2022秋季大会  2022.9 

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    Country:Japan  

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  • チタン石型酸化物における新規反強誘電体の探索

    魚橋毅也, 桑野太郎, 出口和彦, 谷口博基

    セラミックス協会2023年年会  2023.3 

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  • 異価数元素置換したルチル型TiO2 におけるMaxwell-Wagner 効果

    桑野太郎, 橋本友次郎, 出口和彦, 谷口博基

    セラミックス協会2023年年会  2023.3 

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  • チタン石型酸化物CaTi(Si1-xGex)O5の分極特性

    渡邉匠海, 桑野太郎, 中埜彰俊, 横田紘子, 佐藤幸生, 出口和彦, 谷口博基

    日本物理学会2023年春季大会  2023.3 

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  • 異価数元素の固溶によるルチル型TiO2の誘電特性制御

    桑野太郎, 橋本友次郎, 出口和彦, 谷口博基

    学術変革領域研究(A) 「超秩序構造科学」 第5回成果報告会  2023.3 

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  • Insulation of Aliovalent-doped Rutile-type TiO2 International conference

    Taro Kuwano, Yujiro Hashimoto, Kazuhiko Deguchi, Hiroki Taniguchi

    788. WE-Heraeus-Seminar "Beyond Imperfections: New Structure-Property Relationships in Ceramics and Glasses"  2023.5 

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    Language:English   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Country:Japan  

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Awards

  • 第44回電子材料研究討論会最優秀発表賞

    2024.11   日本セラミックス協会電子材料部会   新規チタン石型酸化物PbTiGeO5の誘電特性と固溶体の作製

    桑野太郎

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    Award type:Award from Japanese society, conference, symposium, etc.  Country:Japan

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  • 第46回(2019年春季)応用物理学会講演奨励賞

    2019.5   公益社団法人 応用物理学会   ZnSnP2吸収層/Cu電極界面へのCu3P層の導入による直列抵抗の低減

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    Award type:Award from Japanese society, conference, symposium, etc.  Country:Japan

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Research Projects

  • 反強誘電体チタン石型酸化物をモデルとした分極一次元鎖の強的秩序制御

    Grant number:24K17499  2024.4 - 2026.3

    日本学術振興会  科学研究費助成事業  若手研究

    桑野 太郎

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    Grant amount:\4680000 ( Direct Cost: \3600000 、 Indirect Cost:\1080000 )

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  • 異価数元素共置換によるルチル型TiO2のハイエントロピー化と多機能性複合欠陥の埋め込み

    Grant number:0351155-A  2023.4 - 2024.3

    池谷科学技術振興財団  単年度研究助成 

    桑野太郎

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    Authorship:Principal investigator 

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  • 極薄フラックスを利用したカルコパイライト型リン化物薄膜のMBE成長

    Grant number:21J12760  2021.4 - 2023.3

    日本学術振興会  科学研究費助成事業  特別研究員奨励費

    桑野 太郎

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    Grant amount:\1500000 ( Direct Cost: \1500000 )

    本課題で対象にしたカルコパイライト型無機リン化物半導体ZnSnP2のバンドギャップは、カチオン副格子上のZn/Snアンチサイト欠陥濃度の低下によって、計算では0.7から1.7 eV, 実験的には1.2から1.6 eVまで変化することが報告されている。従って、薄膜太陽電池への応用に向けては、この欠陥の濃度制御が可能な成膜方法が必要である。溶液成長法でバルク結晶を育成する際には、冷却速度によってZn/Snアンチサイト欠陥濃度が制御される。これを分子線エピタキシー(MBE)に応用し、極薄のSn液相からZnSnP2薄膜を析出させられないかと考えたのが、本課題の端緒である。本年度にはMBEにおける成膜温度の影響を調査した。その結果、成膜温度231~317℃の範囲において、Zn/Sn組成比が化学両論比と異なり、Zn/Snアンチサイト欠陥濃度が著しく高いZnSnP2が得られることが分かった。本研究ではまた、粉末試料についてZn/Sn欠陥濃度とラマンスペクトルの相関を調査した。その結果、この欠陥が減少することで、ZnSnP2の特定の振動モードによるラマン散乱の強度が顕著に増大することが分かった。このとき、Zn/Snアンチサイト欠陥濃度、すなわち長範囲規則度とラマン散乱強度との相関が、リンの平均原子位置を媒介として説明されることも明らかとなった。Zn/Snアンチサイト欠陥濃度は従来、X線回折によって評価されてきたが、本研究からラマン分光法による評価も可能であることが提示された。

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