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 a s-deposited films are constituted of islands of rectangular shape and elong ated in the same direction. The electrical characterisation results and the ir variations in the presence of the NO2 gas mixed in low concentration wit h dry air are reported. The electrical response to NO2 gas was studied in o rder to find the optimum detection temperature. The results have shown a re sistance change of about 6000% at a working temperature of 350 degrees C in the presence of 500 ppm of NO2 toxic gas and a sensitivity threshold of ab out 5 ppm at the same working temperature. (C) 1999 Elsevier Science S.A. A ll rights reserved.