engleski

Structural Phase Transition In (Ge2S3)X (As2S3) 1-X Chalcogenide Glasses

Most of the glassforming systems are well described by the continuous-random-network model of Zachariasen. The concept of average coordination number <r> is an important logical step in this line. Phillips have predicted that when the average coordination number <r> of a covalent network glasses in mechanical equilibrium equals an optimal value of 2.4, a condition for critical behaviour exists. In contrast, for chalcogenide glasses, Tanaka suggested that there exists a structural phase transition at the average coordination number of 2.67. Here we present compositional dependence of the structural optical and mechanical properties in ternary Ge-As-S chalcogenid glass. The chalcogenide glass thin films (Ge2S3) x (As2S3) 1-x, with x=0.3, 0.5, 0.7, and 0.9, were prepared by flash thermal evaporation of glass powders on c-Si substrate. The film thickness for all glasses was 100 nm. The Raman scattering experiments were carried out using 514.5 nm laser excitation and triple monochromator. Infrared spectra were recorded in far infrared region with Perkin-Elmer FTIR spectrometer. Energy gap was deduced from absorption spectra...

Structural Phase Transition; Chalcogenide; Glasses; Raman

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