Silver environment and covalent network rearrangement in GeS3–Ag glasses

Abstract

The structure of Ag-doped GeS3 glasses (0, 15, 20, 25 at.% Ag) was investigated by diffraction techniques and extended x-ray absorption fine structure measurements. Structural models were obtained by fitting the experimental datasets simultaneously by the reverse Monte Carlo simulation technique. It is observed that Ge has mostly S neighbours in GeS3, but Ge–Ge bonds appear already at 15% Ag content. Sulfur has ∼2 S/Ge neighbours over the whole concentration range, while the S–Ag coordination number increases with increasing Ag content. Ag–Ag pairs can already be found at 15% Ag. The Ag–S mean coordination number changes from 2.17 ± 0.2 to 2.86 ± 0.2 between 15% and 25% Ag content. Unlike the As–S network in AsS2–25Ag glass, the Ge–S network is not fragmented upon Ag-doping of GeS3 glass.