ELECTRICAL, OPTICAL AND STRUCTURAL-PROPERTIES OF AMORPHOUS V2O5-TEO2 BLOWN FILMS

Binary vanadium tellurite (V2O5-TeO2) amorphous films, of compositions in the range 10-50 mol% V2O5, and thickness in the range 1-7-mu-m have been prepared by a blowing technique. The optical transmission spectra of these films were measured in the range 190-900 nm and the energy gap E(g), width of the tail of localized states E(e) and refractive index n of the films are evaluated. The refractive index dispersion is fitted to a single oscillator model. A sharp decrease in the value of optical band gap E(g), with a small addition of V2O5 (10 mol%) in Teo2, is observed. The decrease in E(g) is, however, less at higher concentrations of V2O5 in the binary system. The dc activation energy E(a) is considerably less than the optical band gap. IR spectra of pure V2O5, pure TeO2 and V2O5-TeO2 blown films were taken. The absorption peaks in the IR spectra of films are not characteristic of the mere oxide mixture, thus indicating a chemical interaction between the two oxide materials.