Composition influence on the properties of sputtered Sn-W-O films

Sn-W-O thin films, deposited by Rheotaxial Growth and Thermal Oxidation (RGTO) technique, have been investigated. The aim of this work is the compositional and sensing characterization, in order to obtain stable materials for gas sensing. Two kinds of SnO2 based samples are realized: W deposited just after Sn deposition and W deposited on SnO2 already oxidized. The compositional characterization is performed by means of XPS depth profiling technique. Surface topography is studied by means of AFM measurements. Electrical measurements were performed in the presence of some gases of interest in polluting area (CO, NO2 and CH4), in breath analysis (ethanol) and in food control (ethylene).