Chalcogenide Glasses. Part 4. Crystallization and Glass Transition Characteristics in As(2-x)Sb(x)S3 Glass-Forming System

摘要

The crystallization characteristics of As(2-x)Sb(x)S3 chalcogenide glasses with nominal compositions ranging from x=0.0 to 2.0 in a melt quenched bulk form and a thin film form were studied, and a self-consistent model of crystallization mechanism was developed. Scanning electron microscopy and X-ray diffraction analysis were used to examine the microstructure and phases present as a function of composition. Differential scanning calorimetry, both in isothermal and dynamic mode, was utilized to determine the kinetic parameters, glass forming tendency, and glass transition characteristics as a function of composition. All results for the melt quenched bulk glasses were consistent with the proposed model in which; 1) the glasses exhibit two phase heterogeneity consisting of Sb2S3 phase and As2S3 matrix phase, 2) the nucleation sites are at the surface of the bulk in the Sb2S3 phase, and 3) the Sb2S3 crystals grow in the glassy As2S3 matrix by diffusion of antimony atoms through As2S3 phase, and subsequent inter-connection of Sb2S3 phase. The experimental results with the vapor deposited film samples suggested a slightly different model, in which no heterogeneity existed in the as-deposited state.