Enhanced performance of solar-blind UV detectors based on Ti3C2Tx/AlGaN heterojunction

AlGaN is an ideal material for fabricating ultraviolet (UV) photodetectors targeting the solar-blind wavelength range. However, the performance of UV detectors based on AlGaN is still limited by its material quality and effective p-type doping. Herein, we propose an external modulation method by combining AlGaN with two-dimensional MXene (Ti 3 C 2 T x ) to construct Ti 3 C 2 T x /AlGaN heterostructures. It has been shown that Ti 3 C 2 T x undergoes a transition from a metallic material to a semiconductor depending on oxidation, and the performance of Ti 3 C 2 T x /AlGaN detectors could be adjusted accordingly. The effect of oxidation process of Ti 3 C 2 Tx on performance of Ti 3 C 2 T x /AlGaN photodetectors has been investigated systematically. The optimized devices exhibited a rise time of 72 ms and a decay time 30 ms, achieving a responsivity of 3000 mA/W under 270 nm UV light irradiation.