Enhanced performance of solar-blind UV detectors based on Ti₃C₂T_x/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 (Ti₃C₂T_x) to construct Ti₃C₂T_x/AlGaN heterostructures. It has been shown that Ti₃C₂T_x undergoes a transition from a metallic material to a semiconductor depending on oxidation, and the performance of Ti₃C₂T_x/AlGaN detectors could be adjusted accordingly. The effect of oxidation process of Ti₃C₂Tx on performance of Ti₃C₂T_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.