Structure of GeSe4-In and GeSe5-In glasses

(Ge0.2Se0.8)100-xInx and (Ge0.17Se0.83)100-xInx (x = 0, 5, 10, 15 at.%) chalcogenide glasses have been studied with high-energy x-ray diffraction, neutron diffraction and extended x-ray absorption spectroscopy at Ge, Se and In K-edges. The experimental data were modelled simultaneously with the reverse Monte Carlo simulation method. GeSe4/2 tetrahedra are shown to be the main structural units in the binary and ternary glasses investigated. Indium bonds to the excess Se atoms in the ternary Ge-Se-In glasses. While the majority of In atoms have three Se neighbours, some In atoms may be tetrahedrally coordinated by Se.