64Cu tracer diffusion in copper chalcogenide glasses

Cu-64 tracer diffusion coefficients D-Cu were measured for semiconducting Cu2SeAs2Se3 and mixed conducting CuI-As2Se3 glasses. At low copper content (x = 1-2 at.% Cu), the diffusion coefficients are similar in the two systems and can be described within the critical percolation approach found recently for silver chalcogenide glasses. Significant differences in D-Cu were observed at 5 less than or equal to x less than or equal to 25 at.% Cu. The diffusion coefficients in the CuI-As2Se3 system appear to be by three orders of magnitude higher compared to those in the Cu2Se-As2Se3 glasses. The observed differences between the two systems are discussed and compared with superionic conducting silver chalcogenide glasses.