High-Detectivity GaN MSM Photodetectors with Low-Temperature GaN Cap Layers and Ir∕Pt Contact Electrodes

Abstract

GaN-based metal-semiconductor-metal (MSM) UV photodetectors (PDs) with a low-temperature (LT) GaN cap layer and contact electrodes were fabricated. Compared with the conventional contacts, we found that contacts can reduce the dark current. Further, a smaller dark current and larger UV-to-visible rejection ratio obtained from the PD with LT GaN cap layer and contact electrodes were determined. Furthermore, the noise equivalent power and detectivity were respectively obtained as and for the aforementioned PDs.