Abstract

We have found that an arsenic vacancy contributes to the 0.839 eV Cr-related luminescence line in GaAs:Cr and the luminescence center is a complex involving a Cr at a Ga site and an arsenic vacancy in its nearest neighbor, based on systematic studies on high temperature thermal annealing of GaAs:Cr under excess arsenic pressure. This Cr-related deep center luminescence line was assigned as due to intra d-shell transitions in a Cr impurity in GaAs. Recent Zeeman data¹⁾ on this 0.839 eV line have shown that the luminescence center has <111> C_3v axial symmetry rather than T_d symmetry of an isolated Cr at the Ga site in GaAs crystal. This suggests that the contribution of another impurity or defect to the Cr-related center. The chemical identification of this partner of the Cr impurity in GaAs has not definitely been done, though the symmetry of the Cr-related center was confirmed by these Zeeman experiments. We have investigated this Cr-related deep center luminescence with samples prepared by different diffusion conditions of Cr into GaAs. As a result, we have found that the intensity of the 0.839 eV Cr-related luminescence line decreases with increasing the arsenic pressure in a sealed quartz ampoules for Cr diffusion in GaAs. Based on these results we have proposed that an arsenic vacancy is a probable candidate as the partner of the Cr in the complex.^2,3)

© 1984 Optical Society of America