High-performance self-powered solar-blind ultraviolet photodetector based on a 4H-SiC/ZnGa₂O₄ heterojunction and its application in optical communication

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 x 10(4), 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 (Delta E-C = 0.99 eV) and a large valence band offset (Delta E-V = 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.