Elucidation of the emission red-shift with increasing growth temperature of MBE-grown GaInNAs/GaAs quantum wells

The causes were investigated for the photoluminescence red-shift with increasing quantum well growth temperature (T_QW) reported in GaInNAs/GaAs quantum wells grown by molecular-beam epitaxy (Tournie´ et al., 2002; Chauveau et al., 2003). The phenomenon was found to be due to self-annealing, which occurred during the growth of layers on top of the quantum well at typical substrate temperatures T_QW for GaAs growth by molecular-beam epitaxy. This self-annealing induces a blue-shift of the quantum well emission, whose magnitude increases as T_QW decreases. The T_QW-dependent blue-shift is correlated with the presence of In and occurs without noticeable changes in macroscopic alloy composition or quantum well structure. The underlying cause for the increase in blue-shift with decreasing T_QW during self-annealing appears to be an increased number of In-N bonds due to point-defect-assisted diffusion. Possible defects involved are discussed in the paper on a qualitative basis.