Achieving a High-Responsivity and Fast-Response-Speed Solar-Blind Photodetector for Underwater Optical Communication via AlGaN/AlN/GaN Heterojunction Nanowires

Realizing energy-efficient devices with sustainable and independent operation is a large challenge for next-generation photodetection systems in various environments. In this study, we present a high-response and fast-speed ultraviolet photodetector (UV PD) based on the p-AlGaN/AlN/n-GaN nanowires (NWs) heterojunction, which could operate at a 0 V bias for underwater photodetection through the photoelectrochemical (PEC) process. Compared to the UV PD without AlN insertion, the detection performance would be increased to 3–5 times for underwater solar-blind UV detection under the effect of heterostructure band engineering to prevent carrier drift and recombination at 0 V bias under 255 nm illumination. Furthermore, the photoresponsivity and response speed can be further improved by a surface modification strategy to adjust the carrier transport between the nitride semiconductor and electrolyte. These promising results lay a solid foundation for the development of III-nitride high-efficiency, self-powered PEC photosynthesis devices in the future.