Abstract: By analysing the relationship between the density of oxygen vacancies and the surface potential barrier of SnO₂ grain, the effects of the oxygen vacancy density on the electrical conductivity of tin oxide gas sensors, as well as the process of production and recombination of the oxygen vacancies, an oxygen vacancy domination model for electrical conductivity of polyerystalline tin oxide is established. The model explaines the changes in electrical conductivity of the sensors under different sintering conditions. It has been verified by X-ray photoemission spectroscopy measurements.

Key words: Tin oxide, Gas sensitive devices, Multicrystalline, Electrical conductivity