▎ 摘　　要

A strategy of adopting Ga2O3 alloyed with Al element to reduce the oxygen vacancy defect density and enhance the interface barrier height of Ga2O3 heterojunction is proposed to fabricate deep-UV photovoltaic detectors with high thermal stability, high photoresponsivity, and fast response speed. Here, a graphene/(AlGa)(2)O-3/GaN device with a photoresponsivity of -20 mA/W, a rise time of similar to 2 mu s and a decay time of similar to 10 ms is presented at 0 V bias. At the working temperature of 453 K, the device still exhibits a photo-to-dark current ratio (PDCR) of 1.8 x 10(3), which is 1-2 orders of magnitude higher than that of the reported high-temperature deep-UV film detectors. By comparing the formation energy of oxygen vacancy defects and the interface barrier height of the heterojunction at different temperatures in graphene/Ga2O3/GaN and graphene/(AlGa)(2)O-3/GaN systems, the strategy of synthesizing (AlGa)(2)O-3 ternary composite alloy is proved to be reliable for fabricating high-performance deep-UV photovoltaic detectors. The method proposed in this paper can provide reference for the preparation of deep-UV photovoltaic detectors with high photoresponsivity and thermal stability in the future.