Fabrication of metal-semiconductor-metal (MSM) UV photodetectors with Al_0.16Ga_0.84N/GaN heterqstructures

Metal-semiconductor-metal (MSM) ultraviolet photodetectors were successfully fabricated and characterized. Al_0.16Ga _0.84N/GaN heterostructures with HT-AlN interlayer whose thicknesses ranged from 30 to 70 nm were grown on sapphire (0001) to achieve high performance MSM UV photodetectors by MOCVD. The HT-AlN interlayer with a thickness of 30 nm showed the best results in terms of quality, so we fabricated and characterized MSM UV photodetectors with an interdigitated finger pattern using the Al_0.16Ga_0.84N/GaN heterostructure incorporating this layer. Their responsivity was 0.2 A/W under -10 V bias at a sharp cut-off of 330 nm. A fast response time of 15.4 ns was achieved, and the dark current of 3.1 p A/cm² under zero bias shows that low leakage current was achieved.