A sprayed SnO2 thin films for NO2 sensors

SnO2 thin films as NO2 sensor in low concentration range have been obtained by chemical spray deposition technique. The AFM analysis showed that the as-deposited films are constituted of islands of rectangular shape and elongated in the same direction. The electrical characterisation results and their variations in the presence of the NO2 gas mixed in low concentration with dry air are reported. The electrical response to NO2 gas was studied in order to find the optimum detection temperature. The results have shown a resistance change of about 6000% at a working temperature of 3508C in the presence of 500 ppm of NO2 toxic gas and a sensitivity threshold of about 5 ppm at the same working temperature.