Research On Composition, Structure And Properties Of (Ga, In)₂S₃-based Chalcohalide Glasses

Content: Recently Ga2S3-based chalcohalide glasses have attracted much attention according to their possible applications such as ultra-fast all optical switching, rare-earth doped 1.3um fiber amplifier, and etc. In addition, based on the similarity of chemical properties with Ga and In, it can be anticipated that ln2S3-based Chalcohalide glasses also be the leading candidates in the above-mentioned fields. However, to our knowledge, there are few reports about Ga2S3-based especially In2S3-based chalcohalide glasses. Considering the intimate relation among the above-mentioned applications, microstructure and basic properties of materials, understanding and utilization of the basic studying findings are worthwhile from theoretical and practical viewpoints.Utilizing the techniques such as X-Ray diffraction, Raman spectra, Comprehensive thermal analysis, UV-Vis-Near IR and FTIR, and etc., probing and analysis has been made systematically about the relationships of composition, structure and properties within four pseudo-ternary systems: GeS2-Ga2S3-KCl, GeS2-Ga2S3-CsCl, GeS2-In2S3-KCI and GeS2-In2S3-CsCI. The obtained conclusions are as follows:The glass-forming regions within GeS2-In2S3-K(Cs)Cl systems were reported firstly.Similarities and changes of Raman spectra between GaS CsCI glass and bridged molecular Ga2Cl6 were ascribed successfully based on the local surroundings of Cs+and its influence on bridged units Ga2S6-xCIx.Ascriptions and evolutions of Raman spectra within GeS2-Ga2S3-K (Cs) Cl systems were made reasonably in terms of micro-structural variation originating from the introduction of MCI (M=K,Cs) such as: local surroundings of M+ ions and its effect on mixed tetrahedral GaS4-xClx together with edge-shared tetrahedral Ga2S6-xClx.Raman spectra of samples within GeS2-In2S3-K(Cs)Cl systems were reported for the first time. Furthermore, assignments and shifts of spectra on every component serial had been elucidated reasonably according to micro-structural transformation resulting from composition changes.Among the glassy micro-structural network, alkali chlorine MCl(M=K,Cs) exists as the flowing forms: M* ions as Cl for its nearest coordination; Cl atoms enter into glassy network as tetrahedral GaS4.xClx within GeS2-Ga2S3-K (Cs) Cl systems; while Cl atoms enter into amorphous net as tetrahedral(InS4.xClx;mainly)and octahedral (InS6-xClx;lessly) units within GeS2-In2S3-K(Cs)CI systems.With the increase of MCI amount, there is a shift toward shorter wavelength about glassy Urbach absorption edge; a decline of glass transition temperature; and a drop on glassy water-resistance within the above-mentioned four systems.Within GeS2-Ga(In)2S3-CsCI systems, the shift about Urbach absorption edge was reasonably ascribed inspiring from the effect of CsCI on the electronic DOS(density of States); and the descending of water-resistance following the increase of CsCI content was explained successfully based on the effect of CsCI on glassy micro-structural units.Originating from the research of comprehensive thermal properties about the two pseudo-ternary systems: GeS2-Ga(ln)2S3-KCI, the compositions having the best glass-forming abilities were found out: 0.6GeS2-0.2Ga2S3-0.2K.CI 0.7GeS2-0.15In2S3-0.15KCI.