GaN-Based Metal–Insulator–Semiconductor Ultraviolet Sensors with CsF Insulating Layer

Abstract

Nitride-based metal–insulator–semiconductor (MIS) ultraviolet (UV) photodetectors (PDs) with a CsF insulating layer were proposed and fabricated. The dark current was considerably reduced and the UV-to-visible contrast ratio was enhanced by inserting the CsF insulating layer. The noise-equivalent powers (NEPs) were 9.05×10-10, 1.27×10-9, and 2.4×10-9 W, and the normalized detectivity (D*) values were 7.5×107, 5.35×107, and 2.83×107 cm Hz0.5 W-1 for the PD with a 5-nm-thick CsF layer, the PD with a 50-nm-thick CsF layer, and the PD with a 100-nm-thick CsF, respectively, when biased at 1 V.