Acceptor associates and bound excitons in GaAs:Cu

Abstract
The effect of several parameters in the diffusion conditions for copper into GaAs on the 1.36-eV photoluminescence (PL) band and the C0 (1.5026 eV) and F0 (1.4832 eV) bound excitons (BE) has been investigated using photoluminescence techniques. Also, the different behavior of the corresponding centers under heat treatment and cool down after diffusion is reported. The results are discussed in relation to the vast literature on the GaAs:Cu, which is confusing on the relation between the 1.36-eV PL band, C0 and F0 bound excitons and the well-known 0.156- and 0.45-eV acceptors. Here it is concluded that there exists no simple relation between the C0 BE and the 1.36-eV PL band nor is the F0 BE related to any other Cu-related PL band in our samples. Models for the identities of these centers are suggested on the basis of the new experimental data presented in this paper.