High-Temperature Photocurrent Mechanism of \b{eta}-Ga2O3 Based MSM Solar-Blind Photodetectors

Abstract

High-temperature operation of metal-semiconductor-metal (MSM) UV photodetectors fabricated on pulsed laser deposited \b{eta}-Ga2O3 thin films has been investigated. These photodetectors were operated up to 250 {\deg}C temperature under 255 nm illumination. The photo current to dark current (PDCR) ratio of about 7100 was observed at room temperature (RT) while it had a value 2.3 at 250 {\deg}C at 10 V applied bias. A decline in photocurrent was observed from RT to 150 {\deg}C and then it increased with temperature up to 250 {\deg}C. The suppression of the blue band was also observed from 150 {\deg}C temperature which indicated that self-trapped holes in Ga2O3 became unstable. Temperature-dependent rise and decay times of carriers were analyzed to understand the photocurrent mechanism and persistence photocurrent at high temperatures. Coupled electron-phonon interaction with holes was found to influence the photoresponse in the devices. The obtained results are encouraging and significant for high-temperature applications of \b{eta}-Ga2O3 MSM deep UV photodetectors.