Role of Bi and Ga additives in the physical properties and structure of GeSe4-GeTe4 glasses

Abstract The influence of Bi on a structure and physical properties of mixed Ga-containing Ge-Se and Ge-Te glasses is studied. Partially ordered nanoscale regions observed with high-resolution transmission electron microscopy are compared with first sharp diffraction peak parameters determined through neutron and X-ray scattering studies. Nanoindentation measurements show quite small deviations in nanohardness ( H ) and Young's modulus ( E ) values for glasses with 1 and 5 at.% of Bi, while two regions with different mechanical properties are observed for sample with 10 at.% of Bi. Increase in Bi concentration from 1 at.% to 5 at.% leads to a complete opacity of ~2 mm thick glass in a whole IR range of spectrum, while no drastic difference between these two samples is observed by SEM, TEM, XRD and neutron scattering methods. Short-range order features and possible electron defect structure are evaluated using EXAFS/XANES and PAL spectroscopies, respectively.