Investigation on gallium doping Ge-As-S chalcogenide glass and glass ceramics

In this work, bulk chalcogenide glasses (Ge₃₅As₁₀S₅₅)_100-xGa_x (x = 0,1,3,5,7,9) were prepared using the traditional melt quenching method, and glass ceramics were prepared to improve the mechanical properties through heat treatment. Optical, thermal and mechanical properties of the glass and glass ceramic samples were measured by FTIR, DSC and Vickers hardness analysis. Results indicate that glass samples exhibited about 70% IR-transmission around 3–12 µm. The hardness of these pure glasses increased from 231 to 282 kgf/mm² through gallium doping and improvement of melt-quenching conditions. The type of nanocrystals precipitated in the glass ceramics were characterized by XRD. Existence of a γ-Ga₂S₃ crystal phase enhanced the hardness of the glass. Also, the size and distribution of nanocrystals in the microstructure of the glass ceramics were investigated by SEM. The hardness of (Ge₃₅As₁₀S₅₅)₉₃Ga₇ glass reached to 302.6 kgf/mm² by precipitation of nanocrystals with diameter smaller than 500 nm.