Enhanced surface-related ultraviolet–visible photoresponse in carbothermal ZnO nanowires by intertwined single-walled carbon nanotubes

An intertwined single-walled carbon nanotubes (SWCNTs)/carbothermal ZnO nanowires (ZNWs) composite is synthesized using a facile ultrasonic stirring technology, which is deposited on Au-interdigitated electrodes for ultraviolet–visible (UV–Vis) photoresponse enhancement. It is found that the SWCNT attached on ZNW surface optimizes the surface-related chemical processes and provides effective carrier transport strategies, responsible for the improvement in photo-responsivity and photo-sensing speed. The UV–Vis absorption of ZNWs has been improved after compositing with the high-conductive SWCNTs, contributing to the significantly improved photo-conductance. The photodetector based on SWCNT/ZNW composites (CZWs) with an optimal SWCNT content of 0.1 wt% shows a 300% improvement in photocurrent density, a 200% improvement in responsivity, and a 400% improvement in on/off current ratio over the pure ZNWs-based device under a UV irradiation of 3.26 mW cm−2 and a bias voltage of 1.0 V. This synthetic method could be scaled up for large-scale fabrication of CZWs on substrate at low cost for practical photodetecting applications.