Enhancing VOCs gas sensing performance of ZnO thin films via Au nanoparticles surface modification and UV illumination

Abstract

Volatile organic compounds (VOCs), such as isopropanol (IPA), pose significant health and environmental risks, highlighting the need for highly sensitive, selective, and energy-efficient gas sensors. Zinc oxide (ZnO) is a promising sensing material due to its wide bandgap, high electron mobility, and strong gas adsorption properties. However, pristine ZnO sensors often require high operating temperatures and lack selectivity. This study investigates Au nanoparticle-modified ZnO thin films for enhanced IPA sensing under 365 nm UV illumination. ZnO films were deposited via RF sputtering, with Au nanoparticles added using DC sputtering. Structural and compositional analyses were performed using field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), and energy-dispersive X-ray spectroscopy (EDS). Results show that Au nanoparticles act as catalytic sites, improving charge transfer and gas oxidation, thereby enhancing sensitivity. UV-generated charge carriers boost sensor performance. Au-decorated ZnO films exhibit superior response characteristic, with optimal performance at moderate Au loading. UV-assisted operation enables efficient gas detection at lower temperatures, reducing power consumption. These findings contribute to the design of next-generation VOC sensors for environmental and industrial applications.