Study On Composition, Structure And Properties Of The GeS₂-In₂S₃-CsI 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 1.3μm fiber amplifier, and etc. In addition, based on the similarity properties with Ga and In, it can be anticipated that In₂S₃-based chalcohalide glasses also be the leading candidates in the above-mentioned fields. However, to our knowledge, there are few reports about 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 electron probe microanalysis (EPMA), X-Ray diffraction, Raman spectra, Comprehensive thermal analysis, UV-Vis-IR spectra, Femtosecond time-resolved optical Kerr gate technique, and etc., probing and analysis has been made systematically about the relationships of composition, structure and properties of the GeS₂-In₂S₃-CsI pseudo-ternary system. The obtained conclusions are as follows:The glass-forming region of the pseudo-ternary system is ascertained. The amount of dissolved In₂S₃ and CsI are up to 30mol% and 45mol%, respectively.Raman spectra of samples within GeS₂-In₂S₃-CsI system were reported for the first time. Further more, assignments and shifts of spectra on every component serial had been elucidated reasonably according to the local surroundings of Cs⁺ ions, its effect on mixed tetrahedral InS_4-xI_x and micro-structural transformation resulting from composition changes.The microstructure of pseudo-ternary GeS₂-In₂S₃-CsI system is showed as follows: the basic s.u. forming the glass network are GeS_4/2, InS_4-xI_x tetrahedral and ethane-like structure S₃ln-InS₃. With the adding of CsI, the ethane-like structure units gradually disappear. Cs⁺ ions can be dissolved into the glass network as charge compensators for non-bridging sulfurs (NBS) or iodine.The glasses in this pseudo-ternary system have relatively high glass transition temperatures, good thermal stabilities, broad transparencies (0.47-10.5μm) and large refractive indices. With the increase of CsI amount, there is a shift towards shorterwavelength on glassy Urbach absorption edge and a decline of glass transition temperature.The third-order nonlinear susceptibility is estimated to be as large as 5.1xlO"13esu at 820nm in sample 0.6GeS2-0.3In2S3-0.1CsI by femtosecond time-resolved optical Kerr gate technique. The response of Kerr signal is dominantly assigned to the ultrafast distortion of the electron cloud.