Transparent and Conducting TiO2 : Nb Thin Films Prepared by Spray Pyrolysis Technique
1Department of Physics, Masinde Muliro University of Science and Technology, P.O. Box 190, 50100, Kakamega, Kenya
2Department of Physics, Kabarak University, P.o. Private Bag, Nakuru, Kenya.
3Department of Physics, University of Eldoret, P.o. Box 1125, Eldoret, Kenya.
4Ångström Laboratory, Uppsala University, P.O. Box 524, SE.75120 Uppsala, Sweden..
Abstract
Abstract: To date, only sputtering and pulsed laser deposition (PLD) techniques have been employed
successfully to fabricate highly conducting and transparent TiO2 : Nb (TNO) films. In this article, we demonstrate
that transparent and conducting
TiO2
: Nb
films can be made by the spray pyrolysis technique. The films were
deposited on Corning 7059 glass substrates at 500 15˚C using an alcoholic precursor solution consisting of
titanium (iv) is opropoxide and
NbCl5
. The influence of increasing
Nb
concentration on the electrical, optical
and structural properties was investigated. The minimum resistivity, 3.36
-3 10
Ω cm, for
Ti1-xNbxO2
film (x
= 0.15) was obtained after 1 hour post deposition annealing in hydrogen atmosphere at 500˚C. The x-ray
diffraction of hydrogen annealed films showed a polycrystalline anatase (004)-oriented phase without any second
phases. The optical band gap for undoped and doped films lay in the range 3.38 – 3.47 eV. Using dispersion analysis, optical constants were determined from spectro-photometric measurements for films on glass.
