Preparation of ZrO2-SnO2 thin films by the sol-gel technique and their gas sensitivity

Pure and ZrO2-doped SnO2 thin films were prepared on ordinary soda-lime glass sheets by the sol-gel technique, using non-alkoxide SnCl2 . 2 H2O as main precursor, Zr(OC3H7)(4) as dopant, methanol as solvent. The gas sensing properties of the thin films were investigated. The relationship between the gas sensitivity and the gas concentration and working temperature was also studied. The experimental results show that by the ZrO2 dopant, the gas sensitivity of SnO2 thin films was greatly enhanced and the sensing temperature zone of the SnO2 thin film was moved to the low temperature area. The ZrO2SnO2 thin film shows excellent and unique sensing properties to H2S, i.e., good sensitivity, high selectivity, and quick response and recovery behaviour at room temperature. The gas sensing mechanism of SnO2/ZrO2-SnO2 thin films to H2S gas is also discussed.