Gas sensing properties of the fluorine-doped tin oxide thin films Prepared by advanced spray pyrolysis

Transparent conducting fluorine-doped tin oxide (FTO) thin films were prepared onto glass at low substrate temperature by an advanced spray pyrolysis technique, with stannic chloride and ammonium fluoride as precursors. The films were grown at different substrate temperatures varied in the range of 250–340°C. The effect of the substrate temperature on the structural, morphological, and hydrogen sulphide (H2S) gas sensing properties of the films has been investigated. XRD studies confirm tetragonal crystal structure of the films and all the films are found to be polycrystalline in nature. The FTO film prepared at 250°C exhibits the maximum sensitivity (∼ 10 %) at 250°C operating temperature. Further, the effect of palladium sensitization on the H2S sensing properties of the 250°C sample has been studied and an enhanced sensing response was obtained.