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Variation of the conductivity of a thin film of tin dioxide (SnO2) in response to a stepwise change in the content of various impurities present in the gas phase has been studied in a broad range of concentrations. The experimental data are interpreted within the framework of the Roginskii-Elovich model of adsorption kinetics. A gas-pressure-independent parameter characterizing the sensor conductivity variation is established. Using the phenomenon under consideration, it is possible to identify adsorbed gas species.

Variation of the current-voltage (I-U) characteristics of thin-film gas sensors based on tin dioxide (SnO2) in the presence of various gases has been studied in a range of working temperatures from 200 to 450°C. The experimental I-U curves are interpreted assuming that various forms of adsorbed oxygen species are present on the tin dioxide surface and that the adsorbed ions can migrate over the surface with different mobilities. Features of the observed phenomena can be used for selecting working temperatures at which an analysis of the I-U curves can provide a basis for the identification of various species adsorbed on the same sensor.

The experimental current-voltage (I–U) curves of thin-film structures based on tin dioxide (SnO2) exhibit nonlinearity in the range of strong applied electric fields. The results of I-U measurements are interpreted within the framework of a model that assumes the drift of adsorbed ions over the film surface. The observed phenomenon can be used both for detecting the impurities in air and for recognizing the types of adsorbed species.