Mechanism of enhancement in NH3 sensing for surface functionalized WO3 film

Abstract

Sensors were fabricated using a screen-printing technique using WO₃ produced by a sol–gel process. Surface functionalization was achieved by using normal and catalyzed SiO₂ coatings. The variation of sensor response to ammonia gas was investigated for both undoped and platinum doped WO₃ sensor layers. The response to ammonia exhibited significant improvement following surface modification with catalyzed silica. The increase has been attributed to an increase in Schottky barrier height.