Physical properties of vanadium pentoxide sol gel films

Vanadium pentoxide films were prepared by an inorganic sol-gel method. Opti cal absorption study of V2O5 yielded a direct band gap of 2.4 eV. The tempe rature coefficient of resistance, beta(tau) was 2% K-1 which indicated that V2O5, could be used as a resistor. The thermoelectric power showed n-type semi-conduction. Thr small changes in the Seebeck coefficient indicated sui tability as a thermistor. The activation energies calculated from the first heating-cooling cycle, were 0.1 and 0.37 eV, which indicated two types of conduction. X-Ray diffraction of V2O5 films showed the three characteristic peaks at 'd' spacing of 0.34, 0.27 and 0.217 nm. Annealing at 573 and 673 K improved the crystallinity of the films and decreased the localized state s in the band gap. (C) 2000 Published by Elsevier Science S.A. All rights r eserved.