Generation of Acceptor Levels in Ge by the Uniaxial Strain - A Theoretical Approach

Abstract

We have studied energetics and atomic and electronic structures of Ge mono-vacancies under biaxial and uniaxial strain. We have found that compressive strain drastically reduce the formation energy of Ge mono-vacancy, and strain induced Ge vacancy formation is expected. Further, our calculations show that energy levels of Ge mono-vacancies sensitively depend on the types of applied strain. In particular, direction of uniaxial strain greatly affects the position of Ge mono-vacancy levels. Our calculation indicates that acceptor levels are easily generated under [110] uniaxial compressive strain. Whereas, acceptor level generation is difficult under [100] uniaxial compressive strain.