UV-A Selective ZnO Thin-Film based Photosensor with Enhanced Detectivity and Linear Dynamic Range

Abstract

In this study, we report a high-quality ZnO thin film synthesized using the sol-gel method for developing a spectrally selective UV photodetector with enhanced detectivity and LDR. The effect of varying precursor concentrations from 1 M to 3 M was systematically examined, with 3 M identified as the optimal concentration. The 3 M ZnO thin film-based planar Ag/ZnO/Ag Metal-Semiconductor-Metal (MSM) structure device has demonstrated dominant photosensitivity of 2.2 × 106 at 350 nm (UV-A) radiation and 20 V applied bias. Additionally, the device exhibited a maximum responsivity of 43 A/W with a full width at half maxima (FWHM) of 38 nm, detectivity of 7.4 × 1013 Jones, external quantum efficiency (EQE) of 15444%, and a linear dynamic range (LDR) of 112 dB at 350 nm (UV-A) radiation and 20 V applied bias. This work presents a cost-effective alternative to traditional methods, highlighting the strong potential of the 3 M ZnO thin film for advanced UV photodetector applications. © 1989-2012 IEEE.