EXAFS studies of Cu+ ion conducting and semiconducting copper chalcogenide and chalcohalide glasses
| Autor: | E.A. Bychkov, Pascale Armand, A. Bolotov, Alain Ibanez |
|---|---|
| Rok vydání: | 1998 |
| Předmět: |
Extended X-ray absorption fine structure
Chalcogenide Coordination number Inorganic chemistry chemistry.chemical_element Conductivity Condensed Matter Physics Copper Electronic Optical and Magnetic Materials Ion chemistry.chemical_compound Crystallography chemistry Materials Chemistry Ceramics and Composites Absorption (chemistry) Stoichiometry |
| Zdroj: | Journal of Non-Crystalline Solids. :314-322 |
| ISSN: | 0022-3093 |
| DOI: | 10.1016/s0022-3093(98)00549-3 |
| Popis: | The short-range order in semiconducting x Cu 2 Se · (1 − x )As 2 Se 3 and mixed conducting x CuI · (1 − x )As 2 Se 3 glasses has been investigated using Extended X-ray Absorption Fine Structure (EXAFS) measurements at the Cu, As and Se K-edges. A non-tetrahedral local coordination of copper, either by Se or by Se and I, has been found in these glassy systems. The pyramidal AsSe 3 units remain essentially intact on introducing Cu 2 Se or CuI. However, the average selenium coordination number, N Se–Y , where Y=As or Cu, increases with x from 2.0 to 2.5–2.6. Simple stoichiometric relationships account for the observed changes in N Se–Y for the Cu 2 Se–As 2 Se 3 glasses, which suggest that, at a nearest neighbour level, the average selenium environment consists of two relatively weakly interacting components coming from vitreous As 2 Se 3 and a hypothetical glassy Cu 2 Se. On the contrary, the EXAFS results indicate that CuI is dispersed in the glass network on a molecular level and interacts with the host matrix. Favourable conductivity pathways, associated with CuI, are suggested to appear in the glass structure, which explain the improved Cu + ion conduction and copper diffusion. |
| Databáze: | OpenAIRE |
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