Photo-plastic effect of zincblende semiconductor crystals and its relationship with quantum structures of dislocation cores

2023 Fiscal Year Final Research Report

• Project/Area Number: 21H04618
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Medium-sized Section 26:Materials engineering and related fields
• Research Institution: Nagoya University
• Principal Investigator: Matsunaga Katsuyuki 名古屋大学, 工学研究科, 教授 (20334310)
• Project Period (FY): 2021-04-05 – 2024-03-31
• Keywords: 転位 / 光照射 / 電子構造

Outline of Final Research Achievements

First-principles calculations and experimental mechanical tests were performed for II-VI group and III-V group compound semiconductors, in order to clarify a physical origin of their photo-plastic effect. It was found that glide-dislocation cores of II-VI group semiconductors have localized electrostatic fields and can interact with excess electrons and holes excited by external light. Moreover, the glide dislocations underwent atomic reconstruction at their cores due to excess carriers. Such reconstructed cores may result in reduced mobility of glide dislocations, which should result in hardening of the systems under external light. Experimental mechanical tests for ZnTe supported this argument. In contrast, glide dislocations in GaP were found to undergo structural transformation from reconstructed to unreconstructed structure in the presence of excess carriers. It can be expected that GaP crystals show softening under light illumination unlike II-VI group semiconductors.

Free Research Field

計算材料科学

Academic Significance and Societal Importance of the Research Achievements

硫化亜鉛単結晶は、通常の白色光下では数％の塑性歪みを示したのち急激な破壊を示す（光硬化現象）のに対し、暗室下では10倍以上の塑性歪みを示す。この申請者らの成果により、従来から脆いと考えられてきた無機結晶であっても、光環境を変えることで、機械的性質を大きく制御できる可能性が広がったといえる。本研究は、この現象の起源を電子・原子レベルで解明した。半導体やセラミックスの無機結晶は、その結晶構造および化学結合性により硬くて脆いと考えられてきた。その常識を覆す成果に対する基本原理を提示したという点で、学術的意義は大きいといえる。