Vibrational Properties of Silver-doped Arsenic Chalcogenide Bulk Glasses

摘要

Silver-doped As_(33)S_(67) and As_(33)S_(33)Se_(33) bulk glasses studied by means of Scanning Electron Microscopy (SEM) and infrared reflectivity, exhibit two-phase glasses, for a wide range of Ag concentration. Using the Effective Medium Approximation we show that the structure is actually a proper average of two components, a Ag-poor and a Ag-rich glass phase. The dominant structural unit in both phases is the pyramidal units AsX_(3/2) units. The latter are arranged in different medium-range order motifs. A detailed analysis of the reflectivity and absorption coefficient spectra made it possible to elucidate the short– and medium–range structural order for the Ag-poor and Ag-rich phases.