Characterization of SnO<sub>2</sub>/TiO<sub>2</sub> Double-Layer Films as Alcohol Sensing Materials

Abstract

The aim of this study is to improve the sensitivity of alcohol sensors by combining the advantages of TiO 2 and SnO 2 films in a double layer device. In this study, an RF magnetron sputtering system was employed to fabricate SnO 2 /TiO 2 double-layer and SnO 2 single-layer films for applications as alcohol sensors. The TiO 2 layer of the SnO 2 /TiO 2 double-layer thin film and the SnO 2 single-layer film were all deposited under various O 2 /Ar ratios of 0.2, 0.4, 0.6, and 0.8. The SnO 2 layer, the top coating of SnO 2 /TiO 2 double-layer, was deposited at a fixed O 2 /Ar ratio of 0.2 with an argon flow rate of 50 seem. 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 SnO 2 /TiO 2 double layer films have better sensitivity and quicker recovery time compared to those of single-layer SnO 2 films.