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

摘要

GaN-based metal-semiconductor-metal (MSM) UV, photodetectors (PDs) with a low-temperature (LT) GaN cap layer and Ir/Pt contact electrodes were fabricated. Compared with the conventional Ni/Au contacts, we found that Ir/Pt 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 Ir/Pt corfjact electrodes were determined. Furthermore, the noise equivalent power and detectivity (D*) were respectively obtained as 2.75 X 10~(-13) W and 1.76 X 10~(12) cm Hz~(0.5) W~(-1) for the aforementioned PDs.