THE CORRELATION OF THE ELECTRICAL AND OPTICAL-PROPERTIES OF THIN-FILMS OF V2O5-BI2O3

The DC conductivity variation with temperature for V2O5-Bi2O3 thin films has been measured and the associated activation energies have been calculated. From these measurements it was concluded that the dominant conduction mechanism at low temperatures was polaron hopping with a transition to freeband conduction at higher temperatures. The refractive index was found to be composition-dependent, and a relationship was found between the conductivity and E(e), the bandwidth of the localized states. The changes in the refractive index, conductivity and E(e) were all found to be consistent with a proposed increase in the concentration of oxygen vacancies. The carrier concentration and mobility were estimated as a function of composition and were found to be inversely related. Finally a tentative model for the energy band structure of the composite is proposed.