Influence of tetrahedral GaS₄/₂ and pyramidal SbS₃/₂ units on optical absorption in Ga–Sb–S chalcogenide glass thin films
Materials Letters, vol.419, 2026 (SCI-Expanded, Scopus)
- Publication Type: Article / Article
- Volume: 419
- Publication Date: 2026
- Doi Number: 10.1016/j.matlet.2026.140958
- Journal Name: Materials Letters
- Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Chemical Abstracts Core, Chimica, Compendex, INSPEC, Academic Search Ultimate (EBSCO), Engineering Source (EBSCO)
- Keywords: Chalcogenide, Chemical bond approach, Glass, Structural units
- Azerbaijan State University of Economics (UNEC) Affiliated: No
Abstract
The optical absorption properties of Ga–Sb–S chalcogenide glass thin films were investigated with respect to the distribution of tetrahedral GaS₄/₂ and pyramidal SbS₃/₂ structural units. Optical transmission spectra of films with different compositions were analyzed using the Tauc method to determine the optical band gap (Eg). The results reveal that Eg strongly depends on the relative fractions of GaS₄/₂-type and SbS₃/₂ -type structural units in the glass network. Increasing Sb content leads to promote the formation of Sb-Sb homopolar bonds, increasing structural disorder and defect states. As a result, the optical band gap decreases from 1.91 eV to 1.25 eV. The observed behavior is explained within the chemical bond approach (CBA) model, demonstrating a direct correlation between local structural organization and optical absorption in Ga–Sb–S chalcogenide glasses.