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 (3 vol%, 6 vol% and 12 vol%) towards 20 ppm H2S gas has been studied. SnO2–CuO multilayered structure having an optimum amount of 3 vol% 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 2 s. 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.