High-resolution XPS for determining the chemical order in chalcogenide network glasses

The power of X-ray photoelectron spectroscopy (XPS) measurements and analysis is demonstrated to establish the structure of network glasses using the examples of binary As-Se, As-S, Ge-Se and Ge-S series. Short-range chemical order in these materials is established, and main building blocks of their structurally-disordered glass network are identified throughout respective glass-forming compositional domains. The XPS fitting procedure is correlated with disproportionality analysis based on the conditions of chemically-ordered bond network model and uniform distribution of constituent chemical elements. The structure of binary As-based glasses (As-Se and As-S) is shown to be adequately described by the terms of 'chain-crossing' model, while 'outrigger raft' model has to be additionally used to build a network of Ge-based glasses (Ge-Se and Ge-S).