Chalcogen passivation of GaAs(1 0 0) surfaces: theoretical study

Abstract In this work, structural and electronic properties of Se- and S-passivated GaAs(1 0 0) surface reconstructions are investigated by density functional theory (DFT) based methods. We have performed total energy minimization of several model geometries of the reconstructed surfaces at different stoichiometry. The common feature is the appearance of a chalcogen layer on top of the Ga terminated surface, forming a Ga-chalcogenid like monolayer. In the case of selenium (Se), monomeric first layer formation is predicted, while in extrem chemically circumstances the sulphur (S) passivated surface can also reconstruct forming S-dimers.