SO2 gas sensor based on vanadium pentoxide thin film

Vanadium pentoxide thin films were prepared with a radio frequency magnetron sputtering method from a compressed V2O5 powder target. X-ray diffraction was used to characterize the structures of the films. The sensitive characteristics of sample films to SO2 were carried out at the temperatures from 300°C to 410°C. Concentration of SO2 was fixed at 0.7g/m3 and the sensing tests were performed in the air with a relative humidity of 90%. The sensing results showed that in the range from 300°C to 390°C, the sensitivity to SO2 by the V2O5 films increased with temperature, while decreased if the temperature is beyond 390°C. Especially, the resistance of V2O5 film could be recovered after removing the target gas without conducting an additional desorbing process at the tested temperatures. A sensing mechanism was proposed in the text too.