Structure of alkali tungsten tellurite glasses by X-ray photoelectron spectroscopy

The electronic structure of two alkali tungsten tellurite glass series: (a) 10Li 2 O.xWO 3 .(90 - x)TeO 2 , and (b) xK 2 O.(10 - x)-Li 2 O.25WO 3 .65TeO 2 has been investigated by X-ray photoelectron spectroscopy. In contrast to alkali tellurite glasses, the core level spectra of the various elements appear unaffected when TeO 2 is replaced by WO 3 , with the alkali oxide concentration remaining constant. The Ols spectra do not indicate a clear separation of the bridging and non-bridging oxygen contributions. Thus we conclude that WO 3 behaves essentially as a network former in tellurite glasses. We have also obtained valence band spectra of the glasses and observed major changes with the addition of WO 3 In particular, the intensity corresponding to the lowest energy part of the spectra, attributed to the 02p bonding orbital, decreases significantly with increasing WO 3 , indicating the appearance of a new bonding configuration.