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

Al-doped Ga2O3 microbelts with widths ranging from 20 to 154 μm and lengths up to 2 mm were grown using carbothermal reduction. Based on these ultra-wide microbelts, single-microbelt (37μm wide) and double-microbelts(38 μm/42 μm wide) metal-semiconductor-metal (MSM) 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 Ga2O3 PD has a very-high photocurrent (Iph) of 192.07 μA and extremely low dark current (Id) of 156 fA at 10 V, and presents a ultra-high light-to-dark current ratio(PDCR) 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, 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 254nm and 365nm 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 Ga2O3 microbelts. .