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

Abstract

Abstract 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 CuNiO 2 /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 × 10 12 Jones, outperforming self‐powered UV PDs based on SiC and Ga 2 O 3 ‐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 A 2 ·Hz −1 and a high cutoff frequency of 5 kHz, enabling it to maintain high‐contrast real‐time reflection imaging capability under solar illumination.