Freestanding ZnO Nanowire Films Derived from Carbon Nanotube Template: Implications for High-Performance UV Photodetectors

Nanowires can provide a large specific surface area and short carrier transport paths in photovoltaic and photoelectric detection devices, improving their photoelectric conversion efficiency and response speed. However, the ability to control the morphology and size of oxide nanowires is still a challenge. In this study, ZnO nanowire arrays were produced using superaligned carbon nanotube (SACNT) films as templates. The control of morphology and structure of oxide nanowires allowed them to grow orderly and be transferred onto any substrate. The as-prepared ZnO nanowires exhibited a unique hollow tubular network structure, which promoted the increase in specific surface area and carrier mobility. After 20 min of sputtering, the peak photoresponsivity of ZnO nanowires was 132% higher than that of directly deposited ZnO thin films. Moreover, it even exceeded the peak photoresponsivity of ZnO thin films at a sputtering time of 60 min, greatly reducing costs and increasing sputtering efficiency. This low-cost scalable method opens up prospects for the development and widespread application of high-performance ultraviolet (UV) photodetectors.