Three-dimensional distribution control of nitrogen atoms in dilute nitride films using atomic layer epitaxy

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K05346
• 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: University of Miyazaki
• Principal Investigator: Suzuki Hidetoshi 宮崎大学, 工学部, 准教授 (00387854)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 希薄窒化物半導体 / 原子層エピタキシー / 太陽電池

Outline of Final Research Achievements

In this study, we fabricated GaAsN thin films in which the spatial distribution of N atoms was three-dimensionally controlled. The N distribution in the GaAsN films was confirmed.
For three-dimensional control, the atomic layer epitaxy (ALE) method, which can control the growth of each atomic layer, was used to control the nitrogen distribution in the growth direction, and the in-plane nitrogen distribution was controlled by surface steps using vicinal GaAs substrates.
By GaAsN growth on substrates with systematically changed step densities, we have quantitatively clarified the amount of N atoms incorporated near the steps and on the terraces of the surface. Using the above result, we have successfully grown GaAsN super lattice with controlling N distribution in three-dimensional.

Free Research Field

結晶成長

Academic Significance and Societal Importance of the Research Achievements

GaAsN等の希薄窒化物半導体は、Nを導入することでGeやSiに格子整合可能でバンドギャップエネルギーを1~2 eVに制御可能であることから、多接合型太陽電池等への応用が期待されている。しかし、N導入による電気特性の悪化が問題である。特性悪化の原因としてN分布の不均一が指摘されているが、実際のN分布の観察は難しい。
そこで本研究では、意図的にN分布を制御したGaAsN薄膜を作製を試み、成長方向と成長面内でN分布を意図的に制御したGaAsN薄膜の作製手法を確立した。今後本手法により作製したGaAsN薄膜の電気特性評価により、N分布の影響が明らかになることが期待される。