Characterization of a nanosized TiO2 gas sensor

Thin films were obtained by r.f. reactive sputtering from a Ti.1W.9 target onto a Si substrate followed by annealing in air at 800 degrees C. The thermal treatment results in a nanosized TiO2 thin film with high surface-to-volume ratio. The nanosized structure, its stability , together with the ease of preparation, make this material suitable as a gas sensor. The sensing layer proved capable to detect 20 ppm of NO2 at a temperature suitable for monitoring of exhaust gases of engines. Its high sensitivity suggests use of this sensor for environmental purposes.