UV-A selective photo-responsivity in a GaN MSM photodetector using ITO schottky electrodes

We examined the AlGaN buffer layer dependent photo-response characteristics of the metal-semiconductor-metal (MSM) UV photodetectors (PDs). In the AlGaN buffer layer PD sample, the peak photo-current was of 4.5 μA at 5 V for 365 nm and dark current level ws 4 pA at 1 V. The UV/visible rejection ratio of AlGaN buffer sample was higher than 10⁴ and HT-GaN/LT-AlN sample was 10² at 1 V, respectively. We observed a UV-A selective (or band-pass-like) response behavior near the 360~370 nm range.