Fabrication and properties of a solar-blind ultraviolet photodetector based on Si-doped β-Ga2O3 film grown on p-Si(111) substrate by MOCVD

A solar-blind ultraviolet photodetector based on p-Si/n-beta-Ga2O3:Si heterojunction, using the Si-doped beta-Ga2O3 as the n-type layer, was fabricated successfully by metal-organic chemical vapor deposition (MOCVD). The current-voltage and photoresponse characteristics of photodetector were investigated. The fabricated p-Si/n-beta-Ga2O3:Si heterojunction photodetector exhibited typical rectification behavior and good solar-blind ultraviolet photoresponse. Sensitive photodetection of current at the reverse bias voltage and stable on-off switching performance were achieved. The photodetector showed a responsivity of 3.76 A/W and a photo-to-dark current ratio of 37.9 under 254 nm illumination. The rise time constants (tau(r1), tau(r2)) and the decay time constants (tau(d1), tau(d2)) of the photodetector under 254 nm illumination at the reverse voltage of - 20 V were estimated to be (0.30 s, 0.76 s) and (0.15 s, 6.15 s), respectively. The fabricated p-Si/n-beta-Ga2O3:Si heterojunction photodetector displayed relatively faster response speed compared to the reported photodetectors based on p-Si/undoped beta-Ga2O3 heterojunction. The results indicate that photodetectors based on p-Si/n-beta-Ga2O3:Si heterojunction have potential development for the high-performance solar-blind ultraviolet photodetectors.