The SnO2 films deposited from inorganic precursors via sol–gel dip coating method have been found to be highly sensitive to
ethanol vapor. An average sensitivity as high as ca. 240 obtained in the films, has been attributed to their nano-crystalline nature as revealed by Glancing angle X-ray diffraction (GAXRD) and Atomic force microscope (AFM). The sensitivity was linear in the low concentration range. The films showed fast response and recovery times. The dependence of grain size of the films on the nature of the substrate and the associated effect on sensitivity has been investigated.