Influence of the bias voltage on the photoluminescence intensity and spectral responsivity of the GaN Schottky barrier photodetector

The effects of the bias voltage on photoluminescence (PL) intensity and the spectral responsivity are studied for an Au/Ni/undoped GaN/n + -GaN structure Schottky barrier photodetector. Near-band-gap PL of GaN quenches at low reverse bias but enhances at high reverse bias. Under high reverse bias, holes are accumulated in the region of the GaN adjacent to the Ni/Au. Only electrons below empty states at top of valence can be excited to the conduction band in this region, which reduces the absorption of near-band-gap luminescence. The decrease of the spectral responsivity for near the band gap under higher reverse bias also supports this assumption.