Sprayed SnO2 thin films for NO2 sensors

SnO 2 thin films as NO 2 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 NO 2 gas mixed in low concentration with dry air are reported. The electrical response to NO 2 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 350°C in the presence of 500 ppm of NO 2 toxic gas and a sensitivity threshold of about 5 ppm at the same working temperature.