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

Abstract

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 × 10⁹ 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 × 10⁹ cm Hz^1/2 W⁻¹ and 0.148 mA W⁻¹, 0.07%, and 7.8 × 10⁸ 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.