C2H4O sensing properties for thick film sensor using La2O3-modified SnO2

Doping SnO2 with Sb was investigated in relation with sensitization of a SnO2-based thick film sensor for C2H4O gas. With Sb doping by 0.05 or 0.1 at.%, the electrical resistances of films lowered drastically, suggesting an optimum Sb doping of about 0.1 at.%. A series of Sb (0.1 at.%)-doped devices with various La2O3 loadings up to 7 wt.% was subjected to measurements of the electrical resistances in air and the sensor response to C2H4O. The highest sensor response to C2H4O at 250 and 300 °C was attained at a loading of 5 wt.%, while the sensor response at 350 °C showed no great difference in between 1 and 7 wt.% loading. The optimal doping and loading amounts were discussed by the basis on the results of SEM observation.