GA K-EDGE EXAFS ANALYSIS ON THE COORDINATION OF GALLIUM IN PBO-GA2O3 GLASSES

Ga K-edge extended X-ray absorption fine structure spectra of(X)PbO-(1 - X)Ga2O3 glasses, where X is 0.7, 0.75 and 0.80 in mole fraction wer e recorded at room temperature to understand the coordination scheme o f gallium in glasses. Analyses of the spectra indicate that most of th e gallium forms GaO4 tetrahedra at the Ga-O bond distance between 0.18 56 and 0.1861 nm with a negligible amount (less than 5% of total Ga-po lyhedra) of GaO6 octahedra. The longer Ga-O bond distance in glasses c ompared to that in beta-Ga2O3 crystal composed of similar GaO4 tetrahe dra indicated the presence of oxygens bonded to three independent cati ons. (C) 1997 Elsevier Science B.V.