ELECTRICAL AND STRUCTURAL CHARACTERIZATION OF THE XCUO - (1-X)V2O5

Semi-conducting glasses in the binary system xCUO:(1-X)V2O5 have been synthesized using the twin-roller quenching technique. The electronic conductivity (sigma) of these glasses has been determined in the 295-473 K range to give a simple Arrhenius relationship. The sigma has been observed to increase to a maximum value of 3.47 X 10(-5) OMEGA-1 cm-1 at T = 295 K with an activation energy E(act) = 0.38 eV for the sample with x = 0.4 as the CuO content is systematically varied. The interatomic distance of vanadium atoms, calculated from density measurements, and E(act) have been found to have an inverse relationship with sigma. X-ray photoelectron spectroscopy (XPS) and X-ray excited Auger electron spectroscopy (XAES) investigations show that vanadium ions are present in reduced oxidation states. The proportion of vanadium ions with oxidation state 4 increases with an increase in CuO content. The electrical behavior of these glasses has been discussed in relation to the XPS and XAES data.