Lattice defects in III-V semiconductors

Abstract

In this work the results of a study of the electronic structure of various lattice defects in III — V compounds are presented. The calculations are carried out by means of a tight-binding scheme with bulk parameters typical of GaAs. The Hamiltonian is solved within the cluster-Bethe-lattice approximation; this method allows us to treat complex defects without much difficulty. Anion and cation vacancies and antisite defects and vacancies around them are considered. The density of states as well as the energy and localization of the bound states are reported. The method allows one to interpret easily upon physical grounds the different features of the electronic structure of the defects. The effect of the ionicity on the electronic structure of antisite defects is also discussed. It is shown that as the ionicity increases, deep level instead of shallow can be introduced in the main gap by those defects.