Devising an advanced WS2/a-Ga2O3 photodetector for high-temperature operation†

High-temperature photodetectors have attracted tremendous attention in recent years due to their potential applications in very large-scale integration (VLSI), industrial manufacturing and aerospace exploration. However, current high-temperature photodetectors usually encounter some challenges, such as complex device structures, low photoresponsivity and poor stability. In this study, a centimeter-scale, ultrathin amorphous gallium oxide (a-Ga₂O₃) film is used for the first time as a heat insulation layer to improve the high-temperature performance of a multilayer WS₂ photodetector. With the help of the a-Ga₂O₃ layer with high heat resistance, the WS₂ photodetector achieves a high photoresponsivity of 73.8 A W⁻¹ at 155 °C, surpassing most other 2D-nanomaterial-based photodetectors. More interestingly, the response time is reduced to 22.9 ms and the specific detectivity reaches as much as 6.64 × 10¹⁰ Jones, values which are much better than those of a WS₂/SiO₂ device (39 ms, 2.87 × 10⁷ Jones) at 125 °C. The WS₂/a-Ga₂O₃ nanodevice has successfully solved the trade-off between device stability and device performance of the photodetector at high temperature, which can be ascribed to the use of the a-Ga₂O₃ film, which can simultaneously enhance the separation efficiency of photogenerated carriers and suppress thermal diffusion from a high-temperature substrate. Our research may provide an efficient strategy to promote the high-temperature applications of 2D-material-based photodetectors.