Influence of electrode material on properties of SnO2-based gas sensor

The influence of electrode material on the properties of oxide semiconductor gas sensor was studied. SnO2 thick films were printed on top of Au and Pt electrodes on alumina substrate using screen-printing technique. The gap between the electrodes was made narrow (approx. 5 mum) to emphasize the effects, which the electrodes might have on the overall conductance and gas-sensing properties of the sensor, at different temperatures. Laser micromachining was used in the fabrication of the electrode structure with the narrow gap. Temperature-stimulated conductance measurements were carried out in different ambient atmosphere conditions in order to have information about the effects that the electrode materials have on the overall sensor conductance. Many different gases at different concentrations in synthetic air were used in the experiments. It is possible to conclude from the results that the interface between the electrode and sensing material has a very important role for the sensing mechanism of tin dioxide gas sensors. (C) 2003 Elsevier Science B.V. All rights reserved.