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Selected glasses of Ge-Se-Te system
Černošková, E. ; Hejdová, M. ; Černošek, Z. ; Holubová, J. ; Todorov, R. ; Vlček, Milan
Bulk glasses Ge30Se70-xTex for (x = 0, 10, 20) were prepared by direct synthesis. Thermal evaporation was used for preparation of thin films. The glass transition temperature of the bulk samples and decrease with increasing Te, but Tg of films with tellurium was not found. Crystallization temperature, Tc, for both bulk samples and films were close each to other. Comparing of Raman spectra - the corresponding Raman bands showed that medium-range order of bulks and thin films are partly different. 77Se MAS NMR of Ge30Se70 glass detected resonance of only Ge-Se-Ge (420 ppm, 98 %) and Se-Se-Se (837 ppm, 2 %), eliminating outrigger raft model and the structure of the studied glasses is probably close to Continuous Random Model.
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Interaction of chalcogenide glasses Ge-As-Se with hexagonal boron nitride
Mastný, L. ; Matušek, M. ; Randáková, S. ; Brožek, Vlastimil
Chalcogenide glasses on the base Ge-As-Se for the applications in infrared optics may content only trace amount of oxygen, because the chemical bonds of the type Ge-O and As-O induce in chalcogenide glasses the generation of absorption bands at the wavelength about 12.8 μm with the consequence of the lowering of optical transmittance of chalcogenide glasses. That is why the chalcogenide glasses must be synthesized in the tubes from special conditioned quartz for to avoid the quartz will be the source of oxygen impurities. The tubes from this quartz are very expensive. The aim of this works is to point out that the chalcogenide glasses may be synthesized also in the tubes from turbostratic hexagonal boron nitride which is refined in the mixture of trichloromethane and ammonia.
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Preparation and characterisation of chalcogenide glasses
Ležal, Dimitrij ; Zavadil, Jiří ; Poulain, M.
Chalcogenide glasses systems AS-S, As-Se, As-S-Se and Ge-Se-Te have been prepared and characterised by absorption spectroscopy, scanning electron microscopy and photoluminescence. Photoluminescence spectra have been measured in wide temperature range and the role of multiphonon transitions in mediating the inner 4f-4f electronic transitions was demonstrated. Peculiar Pr related band at 1600 nm has been found in some samples.
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