Post-growth annealing for enhanced optical performance in dilute nitride III–V semiconductor nanowires

Abstract

The effect of annealing on the optical properties of GaNAs and GaInNAs nanowires (NWs) was systematically studied by room-temperature photoluminescence and electron microscopy. Prolonged annealing at 750 °C for 1 h caused the arsenic desorption and thermal decomposition of GaAs-based NWs, whereas short-time treatments preserved morphology up to 750 °C and induced structural degradation only above 800 °C. Annealing enhanced emission intensity and reduced the spectral linewidth, indicating the suppression of point defects and improved optical uniformity. The most pronounced improvement was achieved under short-time annealing at 750 °C for 3 min, where the photoluminescence intensity reached its maximum. GaNAs showed a small blueshift of about 10 meV, while GaInNAs exhibited only a slight redshift, suggesting negligible In–Ga interdiffusion compared with thin films. These findings demonstrate that short-time, high-temperature annealing under arsenic overpressure is an effective strategy to enhance the optical quality of dilute nitride NWs.