Enhanced ammonia sensing by Sn doped ZnO films prepared by a low-cost fully automated nebulizer spray technique

Abstract

Sn doped ZnO (TZO) thin films were deposited using a homemade nebulizer spray pyrolysis unit on glass substrates. The Sn doping concentration in the starting solution is varied as 2, 4, 6 and 8 at.% and the effect of Sn doping level on the structural, optical, surface morphological and gas sensing properties were investigated. The XRD results reveal that all the films have polycrystalline nature with hexagonal wurtzite structure and the optical studies show that the average transmittance of the deposited films is about 80% in the visible region. All the films show good ammonia gas sensing behavior. Especially, ZnO:Sn film with 6 at.% of Sn doping shows the best response time and recovery time for ammonia gas sensing at room temperature. The AFM results reveal that at 6 at.% of Sn doping, the ZnO film shows maximum roughness and high porosity.