Pyro-phototronic-enhanced self-powered broadband UV photodetector based on GaNQDs/GaN homojunction for deep-UV imaging applications

Broadband ultraviolet photodetectors (BUVPDs), with spectral sensitivity spanning from the deep-ultraviolet band (DUV) to near-ultraviolet band (NUV), offer compact, high-speed, and versatile detection solutions for environmental monitoring, safety, and advanced imaging applications. Herein, we propose and demonstrate a self-powered BUVPD based on a homojunction composed of gallium nitride (GaN) quantum dots and epitaxial GaN. By harnessing the synergistic effects of the pyroelectric and photovoltaic responses, the device exhibits excellent performance, including a high responsivity of 149 mA/W, a specific detectivity of 4.5 × 10¹¹ Jones, and a fast response time of 10 ms. The underlying photo-response mechanism is elucidated via energy band diagram analysis of the GaN homojunction. Furthermore, the influence of ambient temperature on device performance is systematically investigated. Notably, the dark current remains at the pA level across a wide temperature range from 83 K to 373 K. At 373 K, the responsivity shows only a slight deviation from room-temperature values, highlighting the detector's robustness under extreme thermal conditions. Benefiting from its outstanding optoelectronic properties, the device also demonstrates promising deep-UV transmission-mode imaging capabilities under weak light conditions. This work presents a novel design strategy for high-performance BUVPDs and paves the way for next-generation, high-sensitivity deep-ultraviolet imaging technologies.