Sub-ppm NO2 sensors based on nanosized thin films of Titanium-Tungsten oxides

We describe the preparation of thin films of Ti---WO3 obtained by means of r.f. sputtering deposition followed by a thermal oxidation. The sensing characteristics of these thin films were obtained by measuring the response towards NO2 in the interval 0.5–20 ppm and to other interfering gases like ethyl alcohol, CH4 and CO; the influence of water vapour to the response towards NO2 was also investigated. The material seems to be a promising detector of NO2for environmental monitoring