GaInNAs/GaAs quantum well laser structures have been grown by plasma-assisted molecular beam epitaxy. Rapid thermal annealing was applied to suppress the nitrogen-related localized states in the material. These nitrogen-related localized states significantly quench the photoluminescence due to its low radiative recombination efficiency, compared to band-to-band transitions. Further, the thermal excitation processes of carriers from localized states to extended states result in the high temperature-sensitivity of light emission, which may lead to a low characteristic temperature if such structures are used in a laser diode. Our experiments have shown that annealing at 760 degrees C for 120 s is insufficient to totally eliminate the nitrogen-related localized states, which may require a higher temperature anneal process. (c) 2005 American Vacuum Society.