Photoluminescence Study of Defect Formation during Copper Diffusion in Zn-Doped GaAs

Abstract

A new defect center model is proposed to explain the photoluminescence spectra of Zn‐doped GaAs after copper diffusion under extrinsic conditions. These centers introduce a broad band which is located at about 1.37 eV and shows a sharp‐line structure. Photoluminescence data taken from samples Cu‐diffused at different temperatures for different lengths of time are analyzed to obtain the kinetics of the formation of the defect. It is found that the formation kinetics is of first‐order with an activation energy of 1.65 eV. The defects are suggested to be V_AsCu_Ga or D_AsCu_Ga pairs, where V_As and D_As denote, respectively, an arsenic vacancy and a donor impurity occupying an arsenic site.