Coordination of zinc and copper in phosphate glasses by EXAFS

The coordination of Zn2+ and Cu2+ ions in semiconducting phosphate glasses was investigated by EXAFS spectroscopy. A change in Zn coordination occurs when the glass composition deviates from metaphosphate. The results are consistent with the hypothesis that Cu(II) and Cu(I) occupy sites with different coordination geometries, but with entire coordination polyhedra similar for all copper atoms. The consistency of the structural model with the semiconducting properties of the glasses is examined. © 1991.