| Project/Area Number |
21H01629
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Review Section |
Basic Section 26020:Inorganic materials and properties-related
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| Research Institution | National Institute for Materials Science |
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Principal Investigator |
OHSAWA Takeo 国立研究開発法人物質・材料研究機構, 電子・光機能材料研究センター, 主幹研究員 (00450289)
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| Project Period (FY) |
2021-04-01 – 2024-03-31
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| Project Status |
Completed (Fiscal Year 2023)
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| Budget Amount *help |
¥16,770,000 (Direct Cost: ¥12,900,000、Indirect Cost: ¥3,870,000)
Fiscal Year 2023: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2022: ¥3,380,000 (Direct Cost: ¥2,600,000、Indirect Cost: ¥780,000)
Fiscal Year 2021: ¥12,220,000 (Direct Cost: ¥9,400,000、Indirect Cost: ¥2,820,000)
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| Keywords | 酸水素化物 / エピタキシャル薄膜 / 電子物性 / 光電子分光 / 質量分析 / 薄膜 / エピタキシャル成長 |
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| Outline of Research at the Start |
酸化物イオンと水素化物イオンが共存する酸水素化物材料について、触媒作用やヒドリドイオンの高いイオン伝導性の研究が活発化している。荷電状態や構造歪みにより柔軟に変化する物性応答が期待されるが、電子伝導や誘電特性の報告は少ない。本研究では、エピタキシー技術を基盤とし、重水素を用いた遷移金属酸水素化物薄膜の合成へと発展させ、水素濃度や格子歪みを精密に制御して新奇な電子伝導・誘電機能を発現させること、および自発分極や相転移を利用したセンサ素子の実証を行う研究である。
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| Outline of Final Research Achievements |
The objective was to elucidate fundamental electrical conductivity in epitaxial thin films of nanoscale thick oxyhydrides, which are single-crystal films free from grain boundary scattering that is unavoidable in bulk materials. The approach involved the oxyhydrogenation of anatase-type titanium dioxide thin films epitaxially grown by plasma-assisted molecular beam epitaxy. Hydrogen plasma irradiation successfully introduced hydrogen from the thin film surfaces. As a result, the electron concentration could be controlled, successfully inducing an insulator-metal transition. It was observed that these electron concentrations were comparable to the hydrogen concentrations quantified by mass spectrometry, indicating that transparent electrical conductivity could be achieved and controlled through oxyhydrogenation. This technique was extended to complex oxides, and metallic temperature dependence was successfully obtained in oxyhydrogenated thin films of lattice-relaxed barium titanate.
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| Academic Significance and Societal Importance of the Research Achievements |
バルク体では作製が困難であった前周期遷移金属酸化物の酸水素化を、ナノスケール厚のエピタキシャル薄膜で成功した。従来のようなカチオン不純物を必要とせず、薄膜の水素化だけによる透明伝導性の発現と制御を見出した。
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