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.