Low temperature operating SnO_2 thin film sensor loaded with WO_3 micro-discs with enhanced response for NO_2 gas

摘要

Highly sensitive and novel sensor structure comprising of SnO_2 film and WO_3 micro-discs has been developed for trace level detection of NO_2 gas at lower operating temperature. Loading of WO_3 on SnO_2 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× 10~4) with fast response speed (67s) at 100℃. Spill over of NO_2 gas molecules by WO_3 micro-discs on the uncovered surface of SnO_2 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.