Ultrasensitive and High-Speed Ga<sub>2</sub>O<sub>3</sub> Solar-Blind Photodetection Based on Defect Engineering
Xueqiang Ji, Mingyu Liu, Zuyong Yan, Shan Li, Zeng Liu, Xiaohui Qi, Jian-Ying Yuan, Jinjin Wang, Yuanchun Zhao, Weihua Tang, Peigang Li
Abstract
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 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\beta $ </tex-math></inline-formula> -Ga <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> film via oxygen-plasma treatment. As a result, the photodetectors (PD) based on 30 min oxygen-plasma treated Gallium oxide (Ga <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> ) film not only exhibit record-low dark current of 5 fA, over three orders of magnitude times higher responsivity rejection ratio ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${R}_{{250}}/{R}_{{400}}{)}$ </tex-math></inline-formula> , 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 ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.1 \mu \text{W}$ </tex-math></inline-formula> /cm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{{2}}{)}$ </tex-math></inline-formula> with a photo-to-dark current ratio of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sim 10^{{4}}$ </tex-math></inline-formula> . 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 <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> film devices.