Crystal Growth Kinetics and Viscous Behavior in Ge2Sb2Se5 Undercooled Melt

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• 作者：Jaroslav Barták ; Petr Koštál ; Veronika Podzemná ; Jana Shánělová ; Jiří Málek
• 刊名：Journal of Physical Chemistry B
• 出版年：2016
• 出版时间：August 18, 2016
• 年：2016
• 卷：120
• 期：32
• 页码：7998-8006
• 全文大小：605K
• 年卷期：0
• ISSN：1520-5207

文摘

Crystal growth, viscosity, and melting were studied in Ge₂Sb₂Se₅ bulk samples. The crystals formed a compact layer on the surface of the sample and then continued to grow from the surface to the central part of the sample. The formed crystalline layer grew linearly with time, which suggests that the crystal growth is controlled by liquid–crystal interface kinetics. Combining the growth data with the measured viscosities and melting data, crystal growth could be described on the basis of standard crystal growth models. The screw dislocation growth model seems to be operative in describing the temperature dependence of the crystal growth rate in the studied material in a wide temperature range. A detailed discussion on the relation between the kinetic coefficient of crystal growth and viscosity (u_kin ∝ η^–ξ) is presented. The activation energy of crystal growth was found to be higher than the activation energy of crystallization obtained from differential scanning calorimetry, which covers the whole nucleation-growth process. This difference is considered and explained under the experimental conditions.