Effect of rapid thermal annealing on the optical properties of GaAsSb alloys

GaAsSb ternary alloys are fundamental components of advanced electronic and optoelectronic devices in the future. The presence of localized states could greatly affect the optical properties in GaAsSb alloy, which depend on the fluctuation of alloy composition. In order to optimize the optical properties, GaAsSb alloys were treated by rapid thermal annealing (RTA) at different temperatures, and the optical behaviors of the annealed samples were investigated in detail. During RTA, a significant reduction of the localized states was observed by photoluminescence (PL) spectral analysis. Furthermore, the RTA process also altered the distribution of the components of the GaAsSb alloy, which caused a slight red-shift of the maximum PL peak at 150 K. The relationship between the localized states and the temperature of the RTA process was also investigated. The process involving the conversion of localized carriers to free carriers was proposed. Under the suitable RTA conditions, the Sb component was homogenized and the depth of carrier localization was decreased.