R. Golovchak, O. Shpotyuk, M. Iovu, A. Kovalskiy, H. Jain.
Journal of Non-Crystalline Solids, vol. 357, 2011, p. 3454–3460.
The evolution of topology and chemical order along the AsxGexSe1−2x composition-line within the As–Ge–Se glass-forming region is studied by high-resolution X-ray photoelectron spectroscopy. It is shown that cation–cation bond formation becomes a dominant process for the compositions with x > 0.09. The results explain the peculiarities observed around this composition recently in the temperature-modulated differential scanning calorimetry data. Substitution of two selenium atoms within constituent structural units (pyramids and/or tetrahedra) by corresponding cations explains a second peculiarity point at x > 0.16 compositions observed recently with the above technique. The present observations show segregation of As and then Ge at high concentrations of cations in the system (x > 0.20).