Influence of N Interstitials on the electronic properties of GaAsN Alloys

GaAsN alloys contain a significant fraction of interstitial N, which is often reported to act as a scattering and/or trapping center. In some cases, annealing has been reported to reduce the interstitial N fraction, presumably due to N diffusion to As vacancies. However, the influence of interstitial N on the electronic properties of GaAsN alloys remains unknown. In this work, we used annealing to probe the influence of N interstitials on the electronic properties of GaAsN. In as-grown GaAsN films, temperature-dependent Hall measurements reveal a thermally activated increase in free carrier concentration for temperatures above 150 K, suggesting the presence of a defect level below the conduction band edge, presumably due to interstitial N. Upon annealing, the free carrier concentration increases and becomes nearly temperature-independent, indicating a decrease in the concentration of trapping centers, presumably due to a reduced concentration of interstitial N.