SnO2 and SnO2:Pt thin films used as gas sensors

SnO2 and SnO2:Pt thin films, prepared by chemical spray deposition, have been used as gas sensors. The electrical characterization results and their-sensing properties in the presence of CO are reported. The films were grown by chemical spray deposition on glass substrates at different temperatures. The initial solution Was obtained by diluting SnCl4 . 5H(2)O in ethyl alcohol at 0.2 M. In the case of the doped films we have added PtCl2, to the initial solution in the following proportions: 3, 5 and 8% at. The conductance of the films was calculated from the electrical resistance which was measured as a function of measuring temperature, thickness and Pt concentration in the solution. The values of the sensitivity for 3.8 torr of CO partial pressure are as high as 5 for SnO2 and 4 x 10(2) for SnO2:Pt. Additionally we report results on surface topography and crystalline structure. (C) 1997 Elsevier Science S.A.