Influence of CsCl addition on the nanostructured voids and optical properties of 80GeS2-20Ga2S3 glasses

• Void evolution are studied in GeSe2-Ga2Se3-CsCl glasses.
• The CsCl content results in white shift of in the visible transmission.
• The CsCl additions into Ge-Ga-S chalcogenide glasses leading to specific void agglomeration.
• Larger concentrations of CsCl may lead to “supersaturation” of base glasses.

The influence of CsCl content on the void evolution in (80GeS2-20Ga2S3)100-x(CsCl)x, x = 0; 5; 10; 15, chalcogenide glasses and changes of the optical response of these glasses due to CsCl addition are investigated. It is shown that structural agglomeration of voids occurs at addition and increasing of CsCl amount in base glasses. Supersaturation of GeS2-Ga2S3-CsCl glasses by CsCl results in the contraction of void volumes in (80GeS2-20Ga2S3)85(CsCl)15. By applying positron-positronium decomposition algorithm it was established that CsCl not only transforms voids in glass, but also forms new positron-trapping sites in Ge-Ga-S glassy matrix. Therefore, CsCl addition results in the shift of fundamental transmission edge in the visible region. It is shown that doping by larger concentrations of CsCl may lead to “supersaturation” of base glasses and that adding 10 mol% of CsCl is apparently an optimal doping level in view of further modification of glasses with rare-earth ions.