Far-infrared investigation of ternary Ge–Se–Sb and quaternary Ge–Se–Sb–Te chalcogenide glasses

•Ternary and quaternary glassy alloys have been prepared using melt quench technique.•Far-IR spectra have been used to study the bonding arrangement in the synthesized glasses.•Ternary Ge19Se63.8Sb17.2 composition was found to be most crosslinked.•Finally, Ge substitution with Te in ternary Ge19Se63.8Sb17.2 composition has been investigated.

Chalcogenide glasses are remarkable materials for remote sensors, infrared imaging and infrared fibers due to their transparency in Far-infrared (IR) region. Far-IR absorption spectra of Ge19Se81 − xSbx (x = 0, 4, 8, 12, 16, 17.2, 20) and Ge19 − ySe63.8Sb17.2Tey (y = 0, 2, 4, 6, 8, 10) have been obtained in the range of 30–350 cm− 1. Three possible bond arrangement approaches viz. chain-crossing model (CCM), random-covalent-network model (RCNM) and chemical bond approach (CBA) have been used to discuss the formation of bonds. Results are explained on the basis of GeSe4, GeSe2 and SbSe3 isolated structural units which have appeared in Ge–Se–Sb system while Se6Te2 rings, GeTe4 tetrahedron, GeTe2, GeSe4 and GeSe2 structural units have appeared for Ge–Se–Sb–Te system.