Defect states and passivation mechanism at grain boundaries of zinc-blende semiconductors

Abstract

Grain boundaries (GBs) are significant in determining the electrical properties of polycrystalline semiconductors. However, the electronic structures and passivation mechanisms of polycrystalline semiconductors remain poorly understood. In this study, we systematically investigated the Σ3 (112) GB properties of several typical zinc-blende semiconductors via first-principles density functional calculations. We found significant differences of Σ3 (112) GB structures and properties between IV/III and V types, where dangling atoms formed new covalent bonds, and II–VI/I–VII types, where dangling atoms formed no new bonds. These different bonding configurations lead to different origins of defect states at GBs. We successfully designed a targeted doping approach to passivate such defect states for different types of semiconductors. We demonstrated the validity of the proposed approach in Σ3 (112) GB of the zinc-blende semiconductors. This work elucidates the defect states at GBs in common zinc-blende semiconductors, rationalizes diverse post-treatment approaches reported in previous experiments, and provides general guidance for defect passivation at the GBs of polycrystalline semiconductors.