Low-Dark Current UV Photodetector Based on Photochemical Reduction Ag-Nanoparticles Decoration ZnO Nanostructure

The fabrication of sensors for detecting ultraviolet (UV) is a significant issue due to prevent the cataracts and carcinoma (a.k.a skin cancer). To improve the sensing performance of photodetectors (PDs) for UV light, we developed zinc oxide (ZnO) nanorods (NRs) decorated with silver nanoparticles (Ag NPs) via photoreduction method under varying conditions (0 and 30 min) and labeled as AG0Z and AG3Z. The surface morphology, crystallinity, and the composition element of AG0Z and AG3Z were observed through thermal field-emission scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray spectroscopy (XPS). The optical properties of AG0Z and AG3Z were confirmed through photoluminescence (PL) spectroscopy. Finally, the dark currents of the AG0Z and AG3Z were $6.99\times 10^{-{9}}$ and $5.71\times 10^{-{10}}$ A, respectively, when the applied voltage was 1 V. Under UV irradiation, the photocurrents of the AG0Z and AG3Z were $3.916\times 10^{-{6}}$ and $3.22\times 10^{-{6}}$ A, respectively. ${I} _{\text {ph}}$ / ${I} _{\text {dark}}$ contrast ratio was improved from 560 of AG0Z to 5640 of AG3Z correspondingly, the improved efficient of the Ag NPs produced a strong electric field after light absorption due to the localized surface plasmon resonance effect.