Preparation of High-Performance UV Photodetectors Based on Growing ZnO Nanowires via Focused Ion Beam Exposure

The precise patterning of micro–nano-scale photosensitive materials is crucial for the preparation of metal–semiconductor–metal (MSM)-type ultraviolet (UV) photodetectors and the integration of photodetector arrays in image sensors. However, current methods for positioning zinc oxide (ZnO) nanowires (NWs) are complex and lack sufficient accuracy. In this work, the growth of ZnO NWs at specific locations in a zinc acetate films using focused ion beam (FIB) exposure was conducted and observed. Four FIB exposure doses were employed to explore the ZnO NW growth characteristics and the influence on UV detecting performance. As the FIB exposure dose grew, the higher responsivity (R), specific detectivity (D*), and high ON/OFF ratios were measured. At an FIB exposure dose of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1600~\mu $ </tex-math></inline-formula>C/cm2, the UV photodetector exhibited the best performance, with an <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on/off</small> ratio of up to 17 445, a responsivity of 37.91 A/W, a specific detectivity of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4.50\times 10^{13}$ </tex-math></inline-formula> Jones, and an external quantum efficiency (EQE) of 12 879.01%. Additionally, the UV photodetector fabricated with a 1600-<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu $ </tex-math></inline-formula>C/cm2 dose demonstrated a rapid response time of 10.17 s and a recovery time of 7.45 s. This study evaluates the influence of FIB exposure dose on ZnO NW growth and showcases the performance of UV photodetectors fabricated with different doses, providing new insights into ZnO NW growth and methods for optimizing the performance of ZnO NW-based UV photodetectors.