Ultra-high PDCR(>109) of vacuum-UV photodetector based on Al-doped Ga2O3 microbelts

Abstract Al-doped Ga 2 O 3 microbelts with widths ranging from 20 to 154 μ m and lengths up to 2 mm were grown using carbothermal reduction. Based on these ultra-wide microbelts, single-microbelt (37 μ m wide) and double-microbelts(38 μ m/42 μ m wide) metal-semiconductor-metal photoconductive ultraviolet (UV) detectors PDs were fabricated and their optoelectronic performances were investigated at Vacuum-UV (VUV) wavelengths of 185 nm. Under irradiation of 185 nm, the Al-doped Ga 2 O 3 PD has a very-high photocurrent ( I ph ) of 192.07 μ A and extremely low dark current ( I d ) of 156 fA at 10 V, and presents a ultra-high light-to-dark current ratio of 1.23 × 10 9 . The responsivity ( R ), external quantum efficiency (EQE), and detectivity ( D* ) of the double-microbelts detector device were 1920 A W −1 , 9.36 × 10 5 %, and 8.6 × 10 16 Jones, respectively. Since the bandgap of the Al-doped microbelts becomes wider, and the fabricated detector has weaker sensitivity to radiation in the 254/365 nm wavelengths. Compared with the 254 nm and 365 nm UV cases, the devices under 185 nm VUV show the excellent high selectivity ratios of 1.47 × 10 6 and 1.7× 10 7 , respectively. This paper should provide a new insight on the VUV photodetectors utilizing Ga 2 O 3 microbelts.