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They are easy to synthesize in bulk and thin film forms and their compositional flexibility allows tuning of optical properties such as refractive index making them ideal for infrared photonics. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. Chalcogenide glasses (Ch Gs) are amorphous compounds containing the chalcogen elements (S, Se, Te) and exhibit wide infrared transparency windows.
Although such behavior is consistent with the continuously-alloyed structural model, it should be contrasted with the response of the network to the removal or addition of Ba Se.
In the latter case especially, the network responds with the formation of non-bridging Se atoms, which is reminiscent of the charge-compensated structural scenario.
We exploit the photosensitivity of As2S3 glass to build silicon-based tunable photonic devices that offer post-fabrication tuning to optimize performance.
Resonators also serve as a test platform for studying the effects of radiation on silicon and chalcogenide materials systems.
In this thesis, we show that scattering losses dominate in our Ch G microphotonic devices while material attenuation from impurities is low.
We demonstrate resonators coated with nanoporous polymers to improve their selectivity against target analytes for sensing applications.The aforementioned structural conclusions are supported by trends in physical properties.Of all the properties measured, the glass transition temperature Tg responds most predictably to changes in glass structure in the sense that the removal of heteropolar (Ga/Ge)-Se bonds from the glassy network consistently results in a decrease in Tg. D.)--University of California, Davis, 2016.; Publication Number: AAT 10124373; ISBN: 9781339824819; Source: Dissertation Abstracts International, Volume: 77-11(E), Section: B.; 177 p.Chalcogenide glasses exhibit unique optical properties such as infrared transparency owing to the low-phonon energies, optical non-linearity, and photo-induced effects that have important consequences for a wide range of technological applications.The structural duality of the Na2Se/Ba Se--Ga2Se 3--Ge Se2 system is best observed in the off-stoichiometric Ba Se--Ga2Se3--Ge Se2 /-Se glasses.Here, the removal of Se from a stoichiometric glass with Ba Se: Ga2Se 3 1 results in Ge-Ge bonds, while its addition in excess of stoichiometry forms Se-Se bonds.These models significantly improve our current understanding of the effects of modifier addition on the structure and properties of chalcogenide glasses, and thus enable a more efficient engineering of these highly functional materials for applications as solid electrolytes in batteries or as optical components in infrared photonics.In general, the underlying stoichiometric Ga2Se3--Ge Se 2 network consists primarily of corner-sharing (Ga/Ge)Se4 tetrahedra, where the coordination numbers of Ga, Ge, and Se are 4, 4, and 2, respectively.This behavior is entirely consistent with the continuously-alloyed structural scenario of chalcogenide glasses.However, for contents of Ga2Se3 greater than about 25--30 mol%, the avoidance of Ga-Ga and mixed Ga-Ge bonds results in the appearance of three-coordinated Se as an alternate mechanism to accommodate the Se deficiency.