Bond engineering for quantum dot formation in nitride semiconductors

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K05268
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 29020:Thin film/surface and interfacial physical properties-related
• Research Institution: Mie University
• Principal Investigator: Ito Tomonori 三重大学, 工学研究科, 招へい教授 (80314136)
• Co-Investigator(Kenkyū-buntansha): 秋山 亨 三重大学, 工学研究科, 准教授 (40362363)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 量子ドット形成機構 / 窒化物半導体 / 計算機シミュレーション

Outline of Final Research Achievements

Quantum dot (QD) formation is theoretically investigated using macroscopic theory on the basis of the results obtained by nanoscopic theory including ab initio-based approach incorporating growth conditions such as pressure and temperature. The computations give good estimates of surface energy γ, misfit dislocation (MD) formation energy Ed, and effective decrease of strain energy α due to the MD formation to predict growth mode diagram with the mode boundary between QD and MD formations. The calculated results successfully clarify crucial factors for orientation-, lattice mismatch-, and growth condition-dependences in the QD formation for various semiconductor heteroepitaxial systems including nitride semiconductors. Furthermore, the growth mode diagrams give guiding principles for the QD formation such as suitable growth conditions realizing surface reconstructions inducing large Ed in addition to well-known large lattice mismatch increasing α.

Free Research Field

結晶工学

Academic Significance and Societal Importance of the Research Achievements

LED照明の基盤材料として知られている窒化物半導体は，その成長過程で形成される量子ドット(直径20 nm程度のナノ構造)を活用することで、情報・環境分野における次世代デバイス開発においても重要な役割を果たすことが期待されている。しかしながら量子ドット形成機構については未だ不明な点が多い。本研究では独自計算手法を用いて量子ドット形成における支配因子を抽出、現実の成長条件下での創成指針を明らかにした。