Crystal growth mechanism of large-domain BaSi2 films by close-spaced evaporation

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K04136
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 21050:Electric and electronic materials-related
• Research Institution: University of Yamanashi
• Principal Investigator: HARA Kosuke 山梨大学, 大学院総合研究部, 准教授 (40714134)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: シリサイド半導体 / 近接蒸着 / 結晶成長

Outline of Final Research Achievements

The close-spaced evaporation (CSE) method is a deposition method for solar cell material BaSi2 with large-area scalability. This study aimed to elucidate the crystal growth mechanism of BaSi2 thin film by CSE, to fabricate single crystal BaSi2 thin film based on the obtained guidelines, and to reveal its physical properties. First, we succeeded in lowering the deposition temperature by 300 °C by mechanical activation of the raw material. By employing this technique, we investigated the impact of deposition temperature on the crystal domain structure. The results indicated that the domains expanded with an increase in substrate temperature and film thickness. Based on this knowledge, we successfully fabricated a single-crystal BaSi2 thin film on a vicinal Si(100) substrate for the first time. Physical properties measurements revealed that the influence of domain boundaries on carrier lifetime is not large.

Free Research Field

電気電子材料工学

Academic Significance and Societal Importance of the Research Achievements

本研究で実施した近接蒸着法への機械的活性化の利用は、おそらく初めて真空成膜プロセスにメカノケミカル効果を活用した成果である。これによって、薄膜結晶成長の分野に新たな手法を加えることができた。また、単結晶薄膜の作製と物性測定の成果は、結晶粒界の影響を排除した物性評価を可能とする成果である。これはより正確な物性の解明につながり、より高効率なBaSi2太陽電池の設計を可能とする。さらに、結晶ドメイン境界がキャリア寿命に大きな悪影響を及ぼさないことは、BaSi2の太陽電池応用において、結晶ドメインサイズに強い制約がないことを意味している。