Photochemical Decoration of Metal and Metal-Oxide Nanoparticles on Highly Oriented SnO₂Nanorod Films for Improved Hybrid Gas Sensors and Photo-Detectors

Abstract

Highly oriented SnO2 nanorods were grown on Si/SiO2 substrates by using the Vapor-Liquid-Solid (VLS) technique; the resulting nanorods were decorated with Au, Ag, and NiO nanoparticles on separated samples using the UV photochemical decoration approach. The pre-decoration precursor solutions were prepared at same molarity ratio and were used for a chemical bath under UV light exposure during the same irradiation time and same solution volume. The as-decorated nanorod films were characterized afterwards using scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy dispersive X-ray analysis (EDX). Chemical sensitivity studies reveal a significant improvement on time responses and selectivity to Ethanol (C2H5OH) and acetone (C3H6O) vapors for SnO2-Au and SnO2-NiO hybrid devices. Photoconductivity experiments show a significant increase on photocurrent densities related with Au and Ag decoration as well as a decrease on photocurrent density related with NiO decoration. The study reported here suggests the selective tuning on gas sensing and photosensitivity properties of SnO2 hybrid devices and the methods used are described and compared in detail.