WO3 nanoclusters-SnO2 film gas sensor heterostructure with enhanced response for NO2

The surface of SnO2 thin film with porous microstructure has been integrated with WO3 nanoclusters using pulsed laser deposition technique and a novel sensor structure has been realized for detecting low concentration of NO2 gas (10 ppm) at a low operating temperature (100 °C). The content of WO3 was found to be very critical and integration of 8 nm thick nanoclusters exhibits a high sensor response of 5.4 × 104 towards 10 ppm NO2 gas with fast response (67 s). The origin of enhanced response characteristics has been analysed in the light of Fermi level and spillover mechanisms and are correlated with the reaction kinetics of NO2 gas on the sensor surface.