Ultrawide‐Bandgap Amorphous MgGaO: Nonequilibrium Growth and Vacuum Ultraviolet Application

Abstract New ultrawide‐bandgap (>6.0 eV) photosensitive materials are in urgent need to meet the requirements of vacuum‐ultraviolet (VUV) photodetection applied in deep space exploration. Here, a nonequilibrium growth method is reported to fabricate amorphous MgGaO (a‐MgGaO) films with an ultrawide bandgap of 6.0 eV and an ultrashort absorption edge of 206 nm by alloying MgO and Ga₂O₃. By combining the as‐grown films with p‐type graphene (p‐Gr) which serves as a transparent conductor, a vacuum‐ultraviolet photovoltaic detector of p‐Gr/a‐MgGaO/n‐SiC (n‐type SiC) is constructed. The device exhibits an excellent VUV spectral selectivity with a VUV (185 nm)/UV (250 nm) rejection ratio exceeding 10³, high photoresponsivity (≈10.3 mA W⁻¹) under 0 V bias, and ultrafast response and recovery time of 1.94 µs and 0.6 ms, respectively. The reported nonequilibrium growth method is expected to have tremendous potential in fabricating ultrawide‐bandgap oxide compounds, and finally facilitate future deep space exploration.