Highly sensitive UV photodetector based on Ag-doped ZnO nanorods grown by hydrothermal process

Abstract

Ultraviolet (UV) photodetector based on doped ZnO are widely reported in literature. However, their sensitivity is limited due to structural defects and morphology. Herein, we present the fabrication and performance of UV photodetectors based silver (Ag)-doped ZnO nanorods. To improve the performance of UV photodetectors based on ZnO nanorods, in terms of sensitivity and current gain, we explored the impact of low Ag doping on the morphology and optical properties of these nanorods. The ZnO nanorods were grown on glass substrates using a hydrothermal process with varying Ag concentration. The I–V characteristics of the ZnO nanorod photodetectors were analyzed under a bias of 5 V. Notably, the addition of Ag significantly improved the photodetector performance, achieving a 9840% increase in photodetection sensitivity at 375 nm under 0.19 mW/cm² UV illumination, compared to non-doped ZnO nanorods. Furthermore, the results highlight how Ag doping alters the wavelength of peak photoresponse and reduces the rise and decay time constants of the photocurrent, thus improving device response. These findings demonstrate the potential of Ag doping to address critical limitations in ZnO-based UV photodetectors and pave the way for their integration into advanced optoelectronic applications.