Correlation between physical, optical and structural properties of sulfide glasses in the system Ge–Sb–S

New quaternary chalcogenide GexSb40� xS50Te10 (x = 10, 20 and 27 at.%) and GexSb40� xS55Te5 (x = 20 and 27 at.%) glasses have been synthesized and the compositions have been characterized applying prompt gamma-ray activation analyses, neutron diffraction, and material density measurements. Using the experimental data, the basic physical parameters, such as average atomic volume, packing density, compactness, average coordination number, number of constrains, average heat of atomization and cohesive energy, of the synthesized glasses are evaluated and the results are discussed in a function of glass composition.

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Evaluation of basic physical parameters of quaternary Ge–Sb-(S,Te) chalcogenide glasses

The far-infrared spectra of Ge 10 Se 90− x Te x where x  = 0, 10, 20, 30, 40, 50 glassy alloys were measured in the wavenumber region 50–650 cm −1 at room temperature. The results were explained in terms of the vibrations of the isolated molecular units. The addition of Te in Ge 10 Se 90 has shown the appearance of GeTe 2 and GeTe 4 molecular units and vibrations of Se–Te bond as Se 8− x Te x mixed rings. The assignment of various absorption bands has been made on the basis of absorption spectra of pure Se, binary Ge–Se, Ge–Te, Se–Te and ternary Ge–Se–Te glassy alloys. The far-infrared transmission spectrum has been found to shift a little towards lower wavenumber side with the addition of Te content to Ge 10 Se 90 . The addition of Te to Ge–Se system replacing Se has found to reduce the Se–Se bonds and Ge–Se bonds and leads to the formation of Se–Te, Ge–Te and Te–Te bonds.

Far-infrared transmission and bonding arrangement in Ge10Se90−xTex semiconducting glassy alloys

Effect of the substitution of S for Se on the structure of the glasses in the system Ge0.23Sb0.07S0.70−xSex

In this paper, we review ongoing progress in the development of novel on-chip, low loss planar molecular sensors that address the emerging need in the field of biochemical sensing. Chalcogenide glasses were identified as the material of choice for sensing due to their wide infrared transparency window. We report the details of manufacturing processes used to realize novel high-index-contrast, compact micro-disk resonators. Our findings demonstrate that our device can operate in dual modalities, for detection of the infrared optical absorption of a binding event using cavity enhanced spectroscopy, or sensing refractive index change due to surface molecular binding and extracting micro-structural evolution information via cavity enhanced refractometry.

Progress on the fabrication of on-chip, integrated chalcogenide glass (chg)-based sensors

New chalcohalide glasses involving Sb 2 S 3 and MXn have been prepared. Glass-forming regions have been shown in the Sb 2 S 3 -MXn binary systems and Sb 2 S 3 -LiF-NaBr, Sb 2 S 3 -LiF-CaCl 2 ternary systems. These glasses are easy to prepare and chemically stable. Depending on the composition, the glass transition temperature, T g , is between 218 and 230°C, the crystallization temperature, T c , is between 270 and 330°C and the difference T c - T g is between 50 and 90°C, permitting the preparation of preforms of considerable size. These glasses are not transparent in the visible range. The infrared transparent wavelength extends up to about 7.5 μm. These glasses are potential condidates for IR transparent glass around 3–7 μm. The value of σ(100–200°C) of the glasses is about 10 −5 Ω −1 cm −1 .

New chalcohalide glasses from the Sb2S3-MXn system

The influence of mixed-cation effect and mixed-anion effect on glass formation is discussed The results show that both mixed-cation and mixed-anion effects are beneficial to glass formation for dynamic reasons and the weak chemical bond introduced by the mixed-anion effect may reduce glass formation of some strong systems, such as ZrF 4 -based and AlF 3 -based glass However, for CdF 2 -based, MnF 2 -based and heavy halide glass, the weak glass formation is enhanced by the mixed-anion effect

The influence of mixed-ion effects on halide glass formation: a review

A method is described for removing trace metals (Fe, Co, Ni, Cu) from ZrOCl2 aqueous solution by simultaneous solvent extraction. The system involving methyl isobutyl ketone (MIBK) as solvent, and ammonium pyrrolidine dithiocarbonate or diethyldithiocarbonate as chelating agent has been researched. The effect of matrix concentration and extraction pH are discussed. The trace metals in a purified ZrOCl2 sample were determined by GFAAS and the results indicate that the Fe content is below 10 ppb, while Co, Ni and Cu contents are each below 5 ppb.

ZrOCl2 for fluoride glass preparation

High purity fluorides of zirconium, barium, lanthanum and sodium have been prepared by a process involving purification and fluorination of raw materials by an aqueous method, dehydration and sublimation The impurities have been determined by graphite furnace atomic absorption spectrometer (GFAAS) The impurity level of iron in the fluorides was about 20 ppb, and those of cobalt, nickel, copper less than 10 ppb

Progress in purification of fluoride optical fiber materials

A new method is proposed, in which ZrO(NO 3 ) 2 substitutes for ZrOCl 2 as the starting material to prepare high purity ZrF 4 . Compared with the ZrOCl 2 method, this improvement offers some advantages in solvent extraction, fluorination and experimental environment. The metal impurities are determined by GFAAS. The concentration of Fe is less than 10 ppb in purified ZrO(NO 3 ) 2 and 20-50 ppb in purified ZrF 4 , in both of which the contents of Co, Ni, Cu are all below 5 ppb

Chengshan Zhang

Papers

New chalcohalide glasses from the Sb2S3-MXn system

The influence of mixed-ion effects on halide glass formation: a review

ZrOCl2 for fluoride glass preparation

Progress in purification of fluoride optical fiber materials

A new preparation route for high purity ZrF4