Improve photo-to-dark current ratio of p-Si/SiO2/n-Ga2O3 heterojunction solar-blind photodetector by inserting SiO2 barrier layer

Abstract

In this study, the solar-blind ultraviolet photodetectors based on p-Si/Ga2O3 and p-Si/SiO2/n-Ga2O3 heterojunctions were fabricated by metalorganic chemical vapor deposition, respectively. Benefitting from the electron-blocking ability of SiO2 dielectric layer insertion, p-Si/SiO2/n-Ga2O3 photodetectors exhibit a very low dark current of 1.14 × 10−12 A, which is 4 orders of magnitude lower than p-Si/Ga2O3 photodetectors (3.22 × 10−8 A). At the same time, a high photo-to-dark current ratio (1.81 × 105) of p-Si/SiO2/n-Ga2O3 photodetectors was obtained under UV light (λ = 254 nm) at −15 V. Meanwhile, the p-Si/SiO2/n-Ga2O3 devices express better photodetection performance, in which the responsivity and EQE are about two times more than that of p-Si/Ga2O3 photodetectors. Furthermore, the photodetector was found to possess impressive photodetection stabilities. Our results indicate that the p-Si/SiO2/n-Ga2O3 photodetector is an excellent candidate for high-sensitivity, ultrafast response solar-blind UV light detection.