AlGaN ultraviolet metal-semiconductor-metal photodetectors with low-temperature-grown cap layers

We report the fabrication of AlGaN metal-semiconductor-metal (MSM) ultraviolet (UV) photodetectors with low temperature (LT)-AlGaN and LT-GaN cap layers. It was found that the dark currents were 8.3 × 10^-9, 3.3 × 10^-12, and 1.1 × 10^-12A under 5 V applied bias while the effective Schottky barrier heights were 0.781, 0.992, and 0.998 eV for the AlGaN photodetectors without a cap layer, with a LT-GaN cap layer and with a LT-AlGaN cap layer, respectively. It was also found that the maximum responsivities were 0.0361. 0.0328. and 0.0315 A/W for the AlGaN photodetectors without the cap layer, with the LT-GaN cap layer and with the LT-AlGaN cap layer, respectively.