Ultrasensitive and Ultrafast Self-Powered Ultraviolet Photodetector Array for Solar-Blind and Weak-Light Imaging

Self-powered ultraviolet (UV) photodetectors (PDs) based on wide bandgap semiconductors (WBGSs) and their heterostructures face challenges in ultrasensitive and ultrafast weak-light detection capabilities. In this work, an 8 × 8 UV photodetector array based on CuNiO₂/SiC p-n heterojunctions is demonstrated to operate in both solar-blind and weak-light conditions. The device achieves a weak-light detection limit of 4.6 nW·mm^-2, a fast response time of 45 ns, and a high responsivity of 104.2 mA·W^-1 and a detectivity of 3.4 × 10¹² Jones, outperforming self-powered UV PDs based on SiC and Ga₂O₃-based WBGSs and their heterostructures. This excellent performance of the device originates from the high interface quality, large built-in electric field, Fowler-Nordheim tunneling (FNT) of charge transport, and enhancing light absorption at the heterostructures. Moreover, the detector exhibits a low noise power density below 10^-22 A²·Hz^-1 and a high cutoff frequency of 5 kHz, enabling it to maintain high-contrast real-time reflection imaging capability under solar illumination.