Thermally oxidized tin black films for gas sensing

The tin dioxide (SnO2) films were been prepared by oxidization of tin black film which was deposited by thermal evaporation. This method can be used for a simple and economical fabrication of a SnO2 gas sensor. These films also have an ultra-porous structure and a grain size in the nanometer. The reduction of particle size to nanometers leads to a dramatic improvement in sensitivity. The particle size and structural properties of SnO2 film were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Through the addition of Pt sol as a catalyst, the SnO2/Pt films acquired an appropriate resistance and stable reaction, though sensitivity decreased. The gas sensing characteristics were also investigated using iso-C4H10, CH4, C3H8, and CO gases.