Photoresponsivity enhancement of W-doped ZnO film/Silicon based devices via silver nanoparticles

Abstract

Silver nanoparticles (Ag NPs) were deposited onto a 2 at.% Tungsten (W)-doped ZnO (WZO)/p-Silicon (p-Si) UV photodetector using a cost-effective sol–gel method. Top-view scanning electron microscopy (SEM) images confirmed the uniform coating of Ag NPs. Cross-sectional SEM analysis revealed a WZO film thickness of 167 nm, including the Ag NP layer. UV–Vis spectroscopy demonstrated high transparency with an average value of 79.5% for the Ag NPs-coated WZO film. The bandgap energy of this film was calculated to be 3.17 eV. The fabricated photodetector, comprising the Ag NP-modified WZO film and p-Si substrate, exhibited superior performance due to enhanced optical and electrical properties. Notably, the device achieved a responsivity (R*) of 4.83 A/W, a sensitivity (S*) of 60.82, and a detectivity (D*) of 5.06 × 10¹² Jones. Compared to the unmodified WZO/p-Si device, the Ag NP-coated photodetector displayed significant improvements: a 26% increase in R*, a 79% increase in S*, and a 53% increase in D*. These findings highlight the potential of incorporating metal nanoparticles into photosensitive devices to optimize light-matter interactions.