2023 Fiscal Year Final Research Report

Characterization and control of defects in low-temperature-grown Bi-based compound semiconductors for novel terahertz wave emitters and detectors

Research Project

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Project/Area Number	21K04910
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Multi-year Fund
Section	一般
Review Section	Basic Section 30010:Crystal engineering-related
Research Institution	Meiji University
Principal Investigator	Ueda Osamu 明治大学, 研究・知財戦略機構(生田), 研究推進員(客員研究員) (50418076)
Co-Investigator(Kenkyū-buntansha)	富永依里子広島大学, 先進理工系科学研究科(先), 准教授 (40634936) 塩島謙次福井大学, 学術研究院工学系部門, 教授 (70432151) 池永訓昭金沢工業大学, 工学部, 准教授 (30512371)
Project Period (FY)	2021-04-01 – 2024-03-31
Keywords	Ｂi系混晶半導体 / MBE / 低温成長 / 結晶欠陥 / THz波受送信素子 / 欠陥評価 / TEM / 凝集体
Outline of Final Research Achievements	In this study, we have investigated microstructures, defects, and electrical and optical properties of low-temperature (LTG) MBE-grown (In)GaAsBi related thin films which are used for photo-conductivity antenna (PCA). First, we have found that (1) in the single crystal thin films, As-precipitates are formed at the thin film/substrate interface, whereas Bi-rich GaAsBi precipitates and Bi-precipitates are formed uniformly in the entire thin film after annealing and that (2) in the case of solid-phase epitaxial growth of amorphous thin films, Bi-rich GaAsBi and Bi precipitates are formed only at the region just above the thin film/substrate interface. Next, we have established a system of optimization of growth conditions for obtaining (In)GaAsBi applicable to PCA, using carrier lifetime measurement. Furthermore, we evaluated two-dimensional photo current property of GaAsBi by scanning internal photoemission microscopy and we found very uniform optical property in the GaAsBi crystal.
Free Research Field	結晶評価
Academic Significance and Societal Importance of the Research Achievements	本研究では、低温MBE成長した(In)GaAsBi系の単結晶および非晶質薄膜を高温での熱処理した場合に、As、Ga-rich GaAsBiおよびBi凝集体などの欠陥が薄膜/基板界面および薄膜中に形成されることを明らかにした。また、これらの欠陥の電気的・光学的特性への影響についても明らかにした。さらに、テラヘルツ光のセンシングを用いた各種システムへの社会実装を実現するためには、そのキーデバイスとなる高性能で、小型・低コストの光伝導アンテナの開発が必須であるが、本研究により新奇(In)GaAsBi系材料の創製および光学的・電気的特性の最適化が不可欠であることを提案できた。