Theoretical study of native defects in III-V semiconductors

Abstract

The local densities of states associated with antisite and vacancy defects in the III-V semiconductors GaAs, GaP, InP, InAs, and AlAs have been studied using the large-cluster recursion approach of Haydock, Heine, and Kelly. The resonant states and localized states induced by these native defects and the associated electron-charge redistributions are calculated and discussed. The principal states in the fundamental energy gaps corresponding to these defects are found to be the following: for ideal cation vacancies, localized ${T}_{2}$ states in the lower parts of the gaps, for ideal anion vacancies, ${T}_{2}$ states in the upper parts of the gaps, and for anion antisite defects, states of ${A}_{1}$ symmetry in the upper parts of the gaps. For cation antisite defects in AlAs and GaAs, no gap states are found. An ideal divacancy in GaAs is found to introduce four gap states. The properties of intrinsic defects near an ideal GaAs-AlAs (100) interface also have been studied. It is found that the interface does not affect the general features of the local density of states induced by the defect. The total electronic energies of interaction between the defects and the interface are calculated by a generalized zeros-and-poles method, and the resulting interactions between the defects and the interface indicate that nonstoichiometry may result there.