Low temperature operating SnO2 thin film sensor loaded with WO3 micro-discs with enhanced response for NO2 gas

Highly sensitive and novel sensor structure comprising of SnO2 film and WO3 micro-discs has been developed for trace level detection of NO2 gas at lower operating temperature. Loading of WO3 on SnO2 film surface in the form of uniformly distributed micro-discs (8 nm thin, 600 μm dia.) was found to enhance the sensing response (5.4 × 104) with fast response speed (67 s) at 100 °C. Spill over of NO2 gas molecules by WO3 micro-discs on the uncovered surface of SnO2 film and subsequently its reaction kinetics at Sn and W sites could be responsible for modulation of depletion width at n–n semiconductor heterojunction and may play an important role in enhanced response characteristics.