GaN-based metal-insulator-semiconductor (MIS) two-dimensional electron gas ultraviolet (UV) photodetectors with sputtered SiO2 insulation and passivation layers were fabricated. With a 5V applied bias and 35mW deuterium lamp irradiation, it was found that the photocurrent to dark current contrast ratio was 2.1×104 for the MIS photodetector with passivation. It was also found that UV to visible rejection ratio of such MIS photodetector with passivation was more than three orders of magnitude, while the responsivity was 0.144A/W with a 5V applied bias and a 350nm incident light wavelength. Such a result was found to be much larger than those observed from the metal-semiconductor-metal photodetector and the MIS photodetector without passivation.
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