Relationship between Gas Sensitivity and Film Structure of SnO2 Thin Film Gas Sensor by Sol-Gel Method

Gas sensing properties of SnO2 films prepared by sol-gel method are investigated to be strongly dependent on the firing temperature conditions. The films obtained at 400 °C have much higher sensitivity than those at 800 °C, being attributed to the fact that the crystallite size of the films linearly increased with the firing temperature. Probable mechanisms to explain the sensing properties are discussed.