A highly sensitive SnO2–CuO multilayered sensor structure for detection of H2S gas

Sensing response characteristics of bare SnO2 thin film and SnO2–CuO multilayered structures having different CuO content (3vol%, 6vol% and 12vol%) towards 20ppm H2S gas has been studied. SnO2–CuO multilayered structure having an optimum amount of 3vol% CuO is found to exhibit a high response of 2.7×104 at a relatively low operating temperature of 140°C, with a fast response time (t90) of 2s. The enhanced sensing response and the fast response speed are due to the porous microstructure of the deposited thin films in the multilayered sensor structures and the spill-over of the dissociated H2S gas molecules by the CuO layers on the surface of sensing SnO2 layers.