Effect of tungsten doping on the ammonia vapour sensing ability of ZnO thin films prepared by a cost effective simplified spray technique

Tungsten (W) doped zinc oxide films (WZO) are deposited using a simplified spray technique with perfume atomizer for gas sensing application. Tungsten doping concentration is varied as 0, 0.5, 1 and 1.5 at.%. Ammonia vapour sensing ability of the prepared samples is studied at room temperature using chemi-resistive method. The results reveal that all the films have good ammonia sensing behaviour. Amongst all the films 1% WZO sample shows the fast response, recovery and high sensing response even towards low concentration of ammonia. The AFM results reveal that 1% WZO sample has maximum roughness and porosity and PL results demonstrate that 1% WZO sample possess more number of oxygen vacancies and zinc interstials which are the major causes for the enhancement of sensing ability.