Ultra‐Sensitive Normally‐Off AlGaN/GaN HEMT Photodetector Array for Multifunctional Optoelectronic Integration

ABSTRACT The growing demands in deep‐space communication, environmental monitoring, and high‐resolution imaging necessitates ultraviolet photodetectors (UV PDs) with ultrahigh sensitivity, robust background radiation rejection, and high integration compatibility. To address this, we report a wafer‐scale UV PD array based on recessed‐gate AlGaN/u‐GaN/p‐GaN high‐electron‐mobility transistors (HEMT). The device exhibits unprecedented UV‐specific performance: exceptional responsivity of 1.16 × 10 6 A W −1 under 365 nm illumination, and a record‐specific detectivity of 1.69 × 10 17 Jones. Its rapid response dynamics (668.4 µs of rise time; 885.4 µs of fall time) and unparalleled UV/visible rejection ratio (R 365 /R 532 = 7.06 × 10 5 ) enable critical functionalities unattainable by conventional detectors. These include multi‐band optical communication, high‐resolution UV imaging immune to ambient light interference, and real‐time environmental UV monitoring via integrated circuit readout. Fabricated with 95% yield on a 10 × 10 array platform, this work establishes a scalable approach for next‐generation UV‐photonic systems.