Plasmonic-based SnO2 gas sensor with in-void segregated silver nanoparticles

Abstract

SnO2/Ag nano-composite layers were produced by magnetron sputtering of Sn1−xAgx alloy on a fused silica (FS) followed by oxidation at high temperature. Silver nano-islands and particles were then segregated inside the SnO2 layer by means of the Kirkendall. A plasmonic-based optical sensing effect is demonstrated for selective detection of acetone and alcohol in the temperature range of 200–400°C. Red- and blue-shifts in the position of the plasmon-resonance peak in optical transmission spectra due to the silver nanoparticles are monitored for different conditions of SnO2+Ag layer formation and gas exposure. A dynamical response of the SnO2/Ag sensor to methane (CH4)/air cycles is measured, and the sensitivity of the sensor as a function of the operation temperature and illumination is determined. The concept of plasmonic-based SnO2 sensors is discussed having in mind two main phenomena: First, the ability of metallic nanoparticles to hold plasmonic resonances which depends on the dielectric properties of surrounding SnO2 layer and second, the possibility of space-limited heating of nanoparticles and the neighbouring region with light, and in this way to control the chemisorption of oxygen on the sensor’s surface.