Structural characterization of Nb-TiO2 nanosized thick-films for gas sensing application

Pure and Nb-doped TiO2 thick-films were prepared by screen-printing, starti ng from nanosized powders. Grain growth and crystalline phase modification occurred as consequence of firing at high temperature. It has been shown th at niobium addition inhibits grain coarsening and hinders anatase-to-rutile phase transition. These semiconducting films exhibited n-type behavior, wh ile Nb acted as donor-dopant. Gas measurements demonstrated that the films are suitable for CO or NO2 sensing. Microstructural characterization by ele ctron microscopy and differential thermal analysis (DTA) highlights the dep endence of gas-sensing behavior on film's properties. (C) 2000 Elsevier Sci ence S.A. All rights reserved.