The electronic structure of defects in amorphous GaAs

Abstract

Abstract The local electronic structure of like-atom bonds and threefold coordinated Ga and As sites (dangling bonds) in amorphous GaAs have been calculated by the tight-binding recursion method. Singly occupied dangling bonds are found to give gap states just inside the band edges, but their relaxed diamagnetic configurations only give band resonances. This behaviour differs from a-Si: H but is similar to that on surfaces of GaAs crystals. Ga-Ga bonds do not give gap states, but isolated As-As bonds give states just below the conduction-band edge.