First-principles study of the vacancy defects in ZnIn2Te4 and CdIn2Te4

Abstract

First-principles calculations were carried out to study the stability and electronic properties of native vacancy defects in the semiconducting ZnIn2Te4 (ZIT) and CdIn2Te4 (CIT). The Zn/Cd and In vacancies are acceptor defects, while the Te vacancy is donor defect. However, the In and Te vacancies dominate in the [Formula: see text]-type and [Formula: see text]-type semiconducting environments, respectively. The Te vacancy is not excited, so it could not compensate the majority of free carriers. The In vacancy prefers to be excited, which generates free hole carriers to compensate the majority of electron carriers. The Zn vacancy is rare in a typical semiconducting environment. Furthermore, all the vacancies induce localized defect states which may be trap centers for the free carriers. Accordingly, these native vacancy defects are destructive for the development of solar cells based on ZIT and CIT, so they should be avoided as much as possible during the growth process.