The photodetectors based on the wide bandgap semiconductor (WBS)/Si heterojunction have attracted more and more attention in recent years due to their excellent photoelectric characteristics and easy integration capabilities. In this work, we have demonstrated a self-powered solar-blind ultraviolet (UV) photodetector based on the ZnGa₂O₄/Si heterojunction. A typical rectification characteristic with a rectification ratio exceeding 10³ within ±5 V can be obtained. At 0 V bias, the −3 dB cutoff wavelength of ∼255 nm and the UV-visible rejection ratio of ∼3 × 10² show that the device has excellent self-powered solar-blind UV detection performance. In addition, the responsivity and the response speed of ZnGa₂O₄/Si heterojunction can be efficiently enhanced by a transient spike current at 0 V bias when turning on and off the 254 nm UV light. The interface pyroelectric effect of the ZnGa₂O₄ film should be responsible for this transient spike photocurrent phenomenon. Our findings in this work pave a feasible way to realize high-performance WBS/Si heterojunction self-powered solar-blind photodetectors.

We report on the fabrication of a crystalline ε-Ga ₂ O ₃ epilayer on a diamond substrate as deep ultraviolet photodetectors for high-temperature operation. Despite their large lattice mismatch, we achieve high quality growth of ε-Ga ₂ O ₃ films on diamond that exhibit a single out-of-plane orientation. A metal-semiconductor-metal photodetector is fabricated based on the crystalline ε-Ga ₂ O ₃ /diamond heterostructure, which exhibits a high photo-to-dark current ratio of 3.67×10 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.

Introduction of an SiO₂ interfacial layer significantly enhanced the performance of a p-Si/n-ZnGa₂O₄ heterojunction solar-blind UV photodetector.

With the urgent demand for low power consumption, environment-friendly, and portable devices, self-powered solar-blind ultraviolet (UV) photodetectors that only rely on built-in electric fields without external power sources have received extensive attention. In this paper, we have demonstrated a self-powered solar-blind UV photodetector based on a 4H-SiC/ZnGa2O4 heterojunction, along with its application in optical communication. At 0 V bias, the device exhibits a peak responsivity of 115 mA/W with an external quantum efficiency of 58.4% at 244 nm, a fast response speed with a rise/decay time of 18.36/16.15 ms, and a high UV-vis rejection ratio of 4.5 × 104, suggesting that the device has an excellent self-powered solar-blind UV photodetection performance. The exceptional performance of the photodetector is mainly attributed to the 4H-SiC/ZnGa2O4 type I heterojunction with a large conduction band offset (ΔEC = 0.99 eV) and a large valence band offset (ΔEV = 0.75 eV), which is determined by the x-ray photoelectron spectroscopy technique. Moreover, the solar-blind UV optical communication is realized by utilizing the 4H-SiC/ZnGa2O4 heterojunction device to receive signals modulated by the solar-blind UV light. This work provides an effective approach to realizing high-performance self-powered solar-blind UV photodetectors and their potential applications in optical communication.