Development of basic process for fabrication of large single crystals of hexagonal boron nitride in wafer shape

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K04231
• 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: Shizuoka University
• Principal Investigator: Hara Kazuhiko 静岡大学, 電子工学研究所, 教授 (80202266)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 六方晶窒化ホウ素 / 化学気相法 / 薄膜 / エピタキシャル成長 / 固有励起子発光

Outline of Final Research Achievements

In terms of process development for the fabrication of hexagonal boron nitride (h-BN) single crystals in wafer form, the final goal has not been achieved because the grain structure of the thin film was not improved to the target level. On the other hand, it is considered technologically significant that the quality of h-BN thin film on sapphire and Si substrates have been improved to the point where it shows the world's highest level of luminescence properties. Specifically, the results of this research can be summarized as follows: (1) fabrication of a sample that shows band-edge luminescence equivalent to that of high-quality bulk crystals by controlling the growth pressure, (2) significant reduction of carbon impurities in the thin film by improving the CVD equipment to a cold-wall type, and (3) the first observation of intrinsic exciton emission from a thin film grown on a Si substrate.

Free Research Field

結晶工学

Academic Significance and Societal Importance of the Research Achievements

サファイアおよびSiを基板とする六方晶窒化ホウ素（h-BN）薄膜としては世界最高レベルの発光特性を示すまで高品質化が図られたことは学術的に有意義と言える。h-BNは2次元材料電子デバイスの他に深紫外光源への応用が期待されている。発光材料としての特徴は、215 nmにシャープな発光を示すことであるが、この波長域の紫外光源は人体に無害な殺菌用のランプとして、昨年からの世界的な新型コロナウイルス感染症の拡大のなか大きな注目を浴びている。本研究で得られた知見により、h-BN薄膜の発光特性をさらに向上できれば、使用しやすいフラットパネル型の殺菌用深紫外光源などの開発に結び付くことが期待される。