Influence of rapid thermal annealing on nitrogen incorporation in GaAsN alloys

GaAsNBi alloys are promising for infrared optoelectronic devices due to their bandgap tunability without significant lattice parameter variation. N-related defects, which often limit device performance, can be manipulated by rapid-thermal annealing (RTA). For example, RTA has been shown to suppress persistent photoconductivity, increase photoluminescence efficiency, and improve electron mobility in GaAsN. Although RTA-induced decreases in [(N-N)As] have been suggested, direct evidence has not yet been presented. Here, we report on the influence of RTA on the dominant N interstitial incorporation and dissociation mechanisms for GaAsN alloys with N compositions ranging from 0.006 to 0.025. X-ray rocking curves suggest that GaAsN films are coherently strained and compositionally stoichiometric, with minimal RTA-induced out-diffusion. Raman spectroscopy reveals a RTA-induced reduction in vibrational modes associated with (N-N)As. Finally, channeling nuclear reaction analysis reveals an RTA-induced decrease (increase) in the total [100] ([111]) yields, suggesting an increase in the fractions of Nsub and (N-As)As interstitial complexes. We will discuss these results along with a comparison of combined Monte-Carlo-molecular-dynamics simulations of channeling yields.