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

Abstract The electronic structure of two alkali tungsten tellurite glass series: (a) 10Li 2 O ·  x WO 3  · (90 −  x )TeO 2 , and (b) x K 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 O1s 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 O2p bonding orbital, decreases significantly with increasing WO 3 , indicating the appearance of a new bonding configuration.