STUDIES ON THE PROPERTIES OF THE ULTRAFINE PARTICLE FILMS OF TIN OXIDE

This paper deals with the gas sensing properties of SnO2 ultrafine particle films made by dc gas discharge activating reaction deposition. The responses of the films to oxidative gases and reductive gases have been discussed. The result shows that in the process of heating and cooling from 25 to 380-degrees-C, the variations of the resistance of the sample are opposite in air and in vacuum (10(-2) Pa). The curve of the work function of the sample varying with the adsorption of oxygen can demonstrate the degree of porous structure to a certain extent. The optimum operating temperature of sensing alcohol is about 235-degrees-C. The alcohol sensing sensitivity of the films, S, is 1.2 at 5 ppm and 20 at 500 ppm.