Optical properties and functionalities of dense excitonic systems in singularity structures

2020 Fiscal Year Final Research Report

• Project Area: Materials Science and Advanced Elecronics created by singularity
• Project/Area Number: 16H06428
• Research Category: Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)
• Allocation Type: Single-year Grants
• Review Section: Science and Engineering
• Research Institution: Yamaguchi University
• Principal Investigator: Yamada Yoichi 山口大学, 大学院創成科学研究科, 教授 (00251033)
• Co-Investigator(Kenkyū-buntansha): 倉井 聡 山口大学, 大学院創成科学研究科, 助教 (80304492)
• Project Period (FY): 2016-06-30 – 2021-03-31
• Keywords: 励起子分子 / 励起子 / 励起子工学 / 混晶半導体 / 窒化物半導体 / 量子井戸 / 局在化 / 低次元化

Outline of Final Research Achievements

We have clarified the huge binding energy of biexcitons in AlGaN-based quantum wells by means of photoluminescence excitation spectroscopy in the deep ultraviolet spectral range. We successfully evaluated the effect of localization on the biexciton binding energy separately from the effect of quantum confinement. In addition, we observed deep ultraviolet stimulated emission on the higher-energy side of spontaneous emission by optical pumping. Based on the temperature dependence of the threshold excitation carrier density for stimulated emission, we clarified that the formation of optical gain was excitonic in origin even at room temperature.

Free Research Field

レーザ分光法による半導体光物性評価

Academic Significance and Societal Importance of the Research Achievements

AlGaN量子井戸構造を対象とした深紫外誘導放出特性の評価により、室温においても光学利得の生成機構への励起子の寄与を見出すことができた。この光学利得の生成機構への励起子の寄与はAlGaN量子井戸構造では初めての実験結果であり、励起子デバイスの実現性を示す重要な知見である。今後、励起子光物性に関する基礎研究と発光デバイスに関する応用研究との融合が進み、励起子工学に関する研究開発分野の飛躍的な発展が期待できることから、その学術的意義は大きいものと考える。