2004 Volume 45 Issue 12 Pages 3318-3323
The aim of this study is to improve the sensitivity of alcohol sensors by combining the advantages of TiO2 and SnO2 films in a double layer device. In this study, an RF magnetron sputtering system was employed to fabricate SnO2/TiO2 double-layer and SnO2 single-layer films for applications as alcohol sensors.
The TiO2 layer of the SnO2/TiO2 double-layer thin film and the SnO2 single-layer film were all deposited under various O2/Ar ratios of 0.2, 0.4, 0.6, and 0.8. The SnO2 layer, the top coating of SnO2/TiO2 double-layer, was deposited at a fixed O2/Ar ratio of 0.2 with an argon flow rate of 50 sccm. The crystal structure and surface morphology of the films were examined by X-ray diffraction (XRD), Grazing Incident X-Ray Diffraction (GID) and Scanning Electron Microscopy (SEM). The sensitivity value of the film can be calculated from the change in the resistance of the film when exposed to alcohol.
The results show that SnO2/TiO2 double layer films have better sensitivity and quicker recovery time compared to those of single-layer SnO2 films.