Self-Powered Photodetectors\nwith Nickel-Doped ZnO\nNanorods for Operation in Low-Light Environments

Abstract

The\ndevelopment of next-generation optoelectronic devices relies\non the necessity for self-powered, fast, and high-sensitivity photodetectors\nwith a wide-spectral response. This Article investigates the impact\nof nickel doping on the growth of ZnO nanorods (79–123 nm diameter)\non a p-type silicon substrate, exploring alterations in photovoltaic\ncharacteristics compared to the pure counterparts. The results reveal\nenhanced performances in devices with nickel doping ranging from 1%\nto 5%, exhibiting superior behavior across tested parameters. Despite\nconsistent morphology and geometric aspects of the grown nanorods,\nthe persistent presence of nickel was evident. Illumination from UV\nand visible light sources demonstrated increased current in <i>I–V</i> plots with rising doping levels, showcasing robust\nphotovoltaic behavior at 0 V and enabling functionality as a self-powered\nphotodetector. Under UV light, self-powered operation was observed\nat an intensity as low as 20 mW/cm², extending beyond 50\nmW/cm² for visible light exposure. These devices exhibit\napplicability in detecting a broad spectrum of solar radiation, as\nevidenced by the influence of the wavelength and light intensity on\nthe photocurrent response at zero bias. With pulsed frequencies of\na 405 nm laser, changes in the photocurrent were observed with variations\nin operating frequency. Hence, a high-performance, wide spectral,\nself-powered photodetector capable of detecting minimal light intensity\nwas fabricated.