Ultrasensitive and High-Speed Ga2O3 Solar-Blind Photodetection Based on Defect Engineering

Oxygen vacancy (VO) defects are ubiquitous in oxide semiconductors and usually served as charge carriers recombination centers to depress the device performance. Herein, a surface VO defect compensation engineering is conducted to modulate the VO and improve the device performance of $\beta $ -Ga ₂ O ₃ film via oxygen-plasma treatment. As a result, the photodetectors (PD) based on 30 min oxygen-plasma treated Gallium oxide (Ga ₂ O ₃ ) film not only exhibit record-low dark current of 5 fA, over three orders of magnitude times higher responsivity rejection ratio ( ${R}_{{250}}/{R}_{{400}}{)}$ , and faster rise and decay speed than the untreated device but also the oxygen-plasma-treated PDs exhibits exceptional sensitivity to detect extremely weak UV signals ( $0.1 \mu \text{W}$ /cm $^{{2}}{)}$ with a photo-to-dark current ratio of $\sim 10^{{4}}$ . Also, it is discovered that the device based on oxygen plasma has excellent photoelectric stabilities. The defect engineering with surface plasma treatment offers an efficient strategy for the high performance of Ga ₂ O ₃ film devices.