Nanoscale-Thick a-Ga₂O₃ Films on GaN for High-Performance Self-Powered Ultraviolet Photodetectors

A super-high-performance self-powered ultraviolet photodetectorconstructed on a p-GaN/a-Ga2O3 p-n heterojunctionwas fabricated by growing nanoscale-thick films of n-type a-Ga2O3 on p-type GaN film using magnetron sputteringat room temperature. This device exhibited a self-powered effect anddual-band UV detection capability. The device showed exceptional photodetectionperformance with a responsivity of 5.65 A/W, I (light)/I (dark) ratio of 2.03 x10(2), and a detectivity of 8.46 x 10(12) cmHz(1/2)W(-1) to 254 nm light irradiationand a responsivity of 43.8 A/W, I (light)/I (dark) ratio of 1.53 x 10(3) and a detectivity of 6.56 x 10(13) cmHz(1/2)W(-1) under 365 nm UV light irradiation of 50 & mu;W/cm(2) light intensity at 0 V, respectively. This outstanding photodetectionperformance might be ascribed to the distanced separation betweenphotogenerated charge carriers that occurs due to the built-in electricfield across the depletion region of the p-n junction of the GaN/a-Ga2O3 thin film. This study shows the GaN/a-Ga2O3 thin-film-based p-n heterojunction UV photodetectorwith both self-powered performance and dual-band UV photodetectionis very promising for practical applications.