Inverted charge states of anion and cation-site vacancies in zincblende semiconductors: Theory

The donor/acceptor character of anion/cation vacancies in III-V and II-VI semiconductors is found to be "invertible" via two different structural modification processes. It is shown that the normally double donor S-site vacancy in ZnS, for example, can be converted into a double acceptor center and, conversely, the normally double acceptor Zn-site vacancy can be transformed into a double donor defect. Additional results from ab initio calculations for ZnSe, ZnTe, CdTe, GaAs, and GaN indicate that similar reversals in charge states can be obtained in these compounds. The amphoteric nature of vacancies has important implications for dopant compensation.