An Al0.6Ga0.4N/Al0.5Ga0.5N metal–semiconductor–metal (MSM) deep-ultraviolet (DUV) photodetector was developed. It possesses both high photosensitivity and high rejection ratios in comparison to photomultiplier tubes (PMTs). The photodetector was designed to have… Click to show full abstract
An Al0.6Ga0.4N/Al0.5Ga0.5N metal–semiconductor–metal (MSM) deep-ultraviolet (DUV) photodetector was developed. It possesses both high photosensitivity and high rejection ratios in comparison to photomultiplier tubes (PMTs). The photodetector was designed to have a two-dimensional electron gas layer at the Al0.6Ga0.4N/Al0.5Ga0.5N hetero-interface, which plays an important role in increasing the photosensitivity. Additionally, for reducing the dark current, a V/Al/Mo/Au electrode was employed as a Schottky electrode with an appropriate barrier height. Upon irradiation with 10 μW/cm2, an extremely low dark current (10−11 A) and high photocurrent (5 × 10−5 A) were achieved at a bias voltage of 5 V. The photodetector was true solar-blind with a cut-off wavelength of 280 nm. A high photosensitivity of 106 A/W and a rejection ratio of 106 were realized under the irradiation of 10 nW/cm2 DUV photons. The present results revealed that the AlGaN/AlGaN MSM DUV photodetector is one of the most suitable candidates for...
               
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