Thickness effect on the gas sensitivity in multilayered sensors based on thin metal films

The multilayered sensors based on the SnO2 / [metal] / metal thin films are produced and investigated at temperatures from 20 degrees C to 300 degrees C in clean and contaminated air. Thickness of the constituent films is varied and the electrical resistance and the XPS depth profiles are measured. It is determined that the resistance response to gases is dependent on the variation of the thickness of the films. The effect is proved to be suitable for optimisation of the characteristics of the multilayered sensors. The metallic character of the conductance in the base film is associated with a unique response to gas in the sensors tested.