Ultrahigh-Responsivity Ultraviolet Photodetectors Based on AlGaN/GaN Double-Channel High-Electron-Mobility Transistors

In this work, high-performance ultraviolet (UV) photodetectors (PDs) based on an AlGaN/GaN double-channel high-electron-mobility transistor (HEMT) were fabricated and investigated using 360 nm illumination. The design of the novel device structure introduces double two-dimensional electron gas channels, which remarkably improve the effectiveness in the collection of photogenerated carriers and make it work as a two-terminal normally off device. The device exhibited a high responsivity of 2.1 × 107 A/W and a high specific detectivity of 1.7 × 1015 Jones under the illumination of 9.7 μW/cm2, indicating the excellent capability of detecting an ultraweak signal. Meanwhile, a distinguished transient performance was also observed when it operated under 500 Hz pulse illumination. Combining fabrication conciseness and outstanding performance advantages, the proposed AlGaN/GaN double-channel HEMT UV PD shows promising potential in the development of next-generation UV PDs.