High-Temperature Deep Ultraviolet Photodetector Based on a Crystalline Ga₂O₃-Diamond Heterostructure

We report the fabrication of a crystalline $\varepsilon $ -Ga2O3 epilayer on a diamond substrate as deep ultraviolet photodetectors for high-temperature operation. Despite their large lattice mismatch, we achieve high quality growth of $\varepsilon $ -Ga2O3 films on diamond that exhibit a single out-of-plane orientation. A metal-semiconductor-metal photodetector is fabricated based on the crystalline $\varepsilon $ -Ga2O3/diamond heterostructure, which exhibits a high photo-to-dark current ratio of ${3.67}\times {10}^{{6}}$ under 254 nm light illumination at the bias of 20 V, a UV/visible rejection ratio of 259, and fast rise (decay) time of 0.323 (0.171) s at room temperature. Furthermore, thanks to the high crystalline film quality, the device responsivity decreases by only 2/3, and the rise (decay) time is 0.325 (0.539) s when the photodetector is operated up to a high temperature of 473 K. This study explores an effective heterostructure design for the application of deep ultraviolet photodetectors at high temperatures.