Tailoring photodetection performance of self-powered Ga2O3 UV solar-blind photodetectors through asymmetric electrodes

Self-powered solar-blind UV detectors are playing an increasingly critical role in the sustainable development of photodetectors with low energy consumption. In this work, the design of electrode structures, including an asymmetric-size structure and an asymmetric-material structure, was proposed to achieve self-powered photodetection function for the solar-blind UV a-Ga2O3 based photodetectors with metal-semiconductor-metal (MSM) structures. The results indicate that the Au/Ti/Ga2O3/Ti/Au photodetector with an asymmetric-electrode-size shows photodetection performances of responsivity (R), external quantum efficiency (EQE), and detectivity (D*) of 0.149 mA W-1, 0.07%, and 3.1 x 10(9) cm Hz(1/2) W-1@0 V, respectively. The asymmetric-electrode-material photodetectors with Au/Ti/Ga2O3/GZO and Au/Ti/Ga2O3/Au structures possess photodetection performances of R, EQE, and D* of 0.591 mA W-1, 0.29%, and 2.9 x 10(9) cm Hz(1/2) W-1 and 0.148 mA W-1, 0.07%, and 7.8 x 10(8) cm Hz(1/2) W-1@0 V, respectively. The electrodes with the asymmetric-size structure and the asymmetric-material structure result in different Schottky barrier heights in the interfaces of the electrodes and films, which are favorable for realizing self-powered performance. The self-powered solar-blind UV a-Ga2O3 based photodetectors have a fast photo-response speed, high stability and high repeatability. These findings provide a promising and facile route to fabricate a-Ga2O3 self-powered solar-blind UV photodetectors with high photodetection.