Anisotropic-Defect Introduction in GaAs by Electron Irradiation

The energy dependence of the introduction rates of the main defects created in GaAs by electron irradiations in the two crystallographic directions [111] and [$\overline{1}\overline{1}\overline{1}$] have been measured. It is demonstrated that the defects introduced are caused by displacements of As atoms and not of Ga atoms, as previously believed. We show that the observed anisotropy can be explained by an orientation dependence of the threshold energy in the range 7-11 eV.