XPS STUDY OF NB-DOPED OXYGEN SENSING TIO2 THIN-FILMS PREPARED BY SOL-GEL METHOD

Titanium dioxide (TiO2) thin films have been prepared using the sol-ge l method and subsequently doped with niobium oxide (Nb2O5) for use in oxygen sensing applications. The chemical composition of the resultant film sensor surface has been investigated using X-ray pholoelectron s pectroscopy (XPS). Films are essentially stoichiometric with carbon as the dominant impurity at the surface. The film electrical resistance has been examined for detection of oxygen at concentrations of 1 ppm t o 1%. Doping resulted in a 40% increase in the oxygen gas sensitivity of the thin films at an operating temperature, as low as 190 degrees C . (C) 1998 Elsevier Science S.A. All rights reserved.