2021 Fiscal Year Final Research Report
Development of an intense terahertz pulse source using semiconductor heterostructures
| Project/Area Number |
19K04540
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 21060:Electron device and electronic equipment-related
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| Research Institution | Osaka Institute of Technology |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
小山 政俊 大阪工業大学, 工学部, 准教授 (30758636)
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| Project Period (FY) |
2019-04-01 – 2022-03-31
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| Keywords | テラヘルツ放射 / GaSb/InAsヘテロ接合 / フォトデンバー効果 / パルス光源 / terahertz radiation / GaSb/InAs / photo-Dember effect / pulse laser source |
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| Outline of Final Research Achievements |
We conducted a study for the development of an intense terahertz pulse source utilizing InAs-based heterostructure. The optical source relies on photo-Dember effect since InAs possesses both high electron mobility and optical absorption coefficient. First, we systematically studied how the terahertz radiation intensity depends on the thicknesses of the GaSb in the GaSb/InAs heterostructures. We found that the radiation intensity increases as the GaSb thickness decreases. We observed an enhanced radiation for GaSb thickness of 5 nm.
In the GaSb/InAs heterostructures, the GaSb layer serves as the absorption layer and injects electrons into the InAs radiation layer. However, GaSb has a lower absorption coefficient than that of InAs. We therefore introduced the InGaSb absorption layer in order to increase the optical absorption. We confirmed that the InGaSb/InAs heterostructures for InSb content of 0.2 show stronger terahertz radiation than those for GaSb/InAs heterostructure.
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| Free Research Field |
化合物半導体デバイス
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| Academic Significance and Societal Importance of the Research Achievements |
テラヘルツ領域で動作する受発光素子の開発は、当該周波数領域の技術の開発、応用を見据え、非常に重要である。中でも、テラヘルツ時間領域分光法による文化財評価への応用は重要で、そのためには簡便に使用できるパルス光源の開発が重要である。本研究は、このテラヘルツパルス光源の開発に関わり、従来使用されている光伝導スイッチが、発光場所が微細な位置に限られ、精密な位置調整や電圧の印加が必要であったことに対し、電圧の印加が必要なく、試料表面全体が発光可能な素子となるため、扱いが容易であり、これからの本分光法の発展に重要である。
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