Structural study of chalcogenide Ge20Se50Te30 glass

The investigations of the crystallization kinetics of Ge20Se50Te30 glass by differential scanning calorimeter (DSC) indicate two-stages glass transition and double-stages crystallization process during phase change. The activation energy of amorphous-crystalline transformation E-c was evaluated by three different methods. The average value of E-c is 17.68 +/- 0.997 kcal/mol at the first peak and 43.06 +/- 0.999 kcal/mol at the second peak. The crystalline phases resulting from (DSC) have been identified using X-ray diffraction and scanning electron microscopy (SEM). From X-ray diffraction results, the first phase is identified as Te and the second phase is GeSe2. The crystallization mechanisms are examined in terms of recent analysis developed for non-isothermal condition. The results indicate that the first separated crystalline phase is a two-dimensional growth, while the second crystalline phase is a three-dimensional process. (C) 2000 Elsevier Science B.V. All rights reserved.