2023 Fiscal Year Final Research Report
Research on growth of high-quality GaAs-based superlattices and stable excitons
| Project/Area Number |
19K05295
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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 30010:Crystal engineering-related
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| Research Institution | Waseda University |
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Principal Investigator |
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| Project Period (FY) |
2019-04-01 – 2024-03-31
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| Keywords | GaAsN / MBE / 励起子 / PL / 光伝導 / 超格子 / AlGaAsN / 電気伝導 |
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| Outline of Final Research Achievements |
GaAsN, AlGaAsN, and GaAsN-based superlattices (SLs) were grown by radio-frequency plasma-assisted solid-source molecular beam epitaxy (RF-MBE) to improve their crystal qualities. As a result, a peak related to an exciton was observed at room temperature in a photoconduction spectrum of GaAsN, showing the stable exciton exists in GaAsN. This result is ascribed to the larger biding energy of an exciton for GaAsN, since the electron effective mass of GaAsN becomes heavier compared with GaAs. A photoluminescence spectrum was also observed for AlGaAsN, since its crystal quality was much improved.
In addition to the above experimental results, we obtained the experimental results related to the S-shape characteristics for GaAsN, the crystal structure of GaAsN, the electron effective mass of GaAsN, and the electrical conduction characteristics of intentionally doped AlGaAsN. Furthermore, we grew high-quality AlGaAsN/GaAsN SL to optimize its growth conditions and their structure parameters.
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| Free Research Field |
半導体工学
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| Academic Significance and Societal Importance of the Research Achievements |
本研究では、窒素組成の低いGaAsNにおいて、励起子の束縛エネルギーが高くなることに注目して研究を進めた。そして、室温において励起子が安定に存在していることを示す実験結果を得ることができた。励起子が安定に存在する場合には、光の吸収が促進されることが知られている。したがって、高品質のGaAsNを用いた薄膜太陽電池では、効率が高くなることが期待される。
また、励起子の束縛エネルギーがさらに高くなることが期待できるAlGaAsNやAlを含むGaAsN系超格子に関して、高品質の薄膜を成長することが可能になった。したがって、今後のGaAsN系超格子に関する励起子などの光学特性の研究の発展が期待される。
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