Prediction of equilibrium defect concentrations in GaAs and ZnSe

Abstract

We use the local density approximation within a self-consistent pseudopotential and pseudoatomic-orbital scheme to predict equilibrium point defect concentrations in semiconductors and their dependence on stoichiometry, temperature and Fermi level. We compare and contrast the native defects expected in GaAs (III–V) with those in ZnSe (II–VI). We find in stoichiometric p-type material that the dominant defect in GaAs is the cation on anion antisite defect, whereas the interstitial cation defect is dominant in ZnSe. The prominence of interstitials in p-type ZnSe tends to self-compensate the material since Zn I is a double donor. We also demonstrate how extrinsic impurities may affect native defect concentrations by considering as an example the Zn impurity in GaAs.