Al-doped Ga2O3microbelts with widths ranging from 20 to 154μm and lengths up to 2 mm were grown using carbothermal reduction. Based on these ultra-wide microbelts, single-microbelt (37μm wide) and double-microbelts(38μm/42μm 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 Ga2O3PD has a very-high photocurrent (Iph) of 192.07μA and extremely low dark current (Id) of 156 fA at 10 V, and presents a ultra-high light-to-dark current ratio of 1.23 × 109. The responsivity (R), external quantum efficiency (EQE), and detectivity (D*) of the double-microbelts detector device were 1920 A W-1, 9.36 × 105%, and 8.6 × 1016Jones, 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 × 106and 1.7× 107, respectively. This paper should provide a new insight on the VUV photodetectors utilizing Ga2O3microbelts.
Keywords: Al-doped Ga2O3 microbelts; MSM; VUV photodetectors; carbothermal reduction.
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