Glass forming tendency in ternaryGexAs20Te80−x glasses examined using differential scanning calorimetry

Abstract

The intermediate composition ofGexAs20Te80−x glasseshas been studied by differential scanning calorimetry. The intermediate glass formation and devitrificationof Ge10As20Te70 is proved more stable than the vicinity of intermediate compositions because the activation energy oftransition, Eg (122.5 kcal mol−1), of this composition shows a minimum at its average coordination numberr = 2.4. The thermal stabilityof intermediate Ge10As20Te70 glass is discussed based on characteristic temperatures such as the glass transition temperature,Tg, the crystallizationtemperature, Tp, and themelting temperature, Tm. The crystallization results are analysed and both the activation energy of the crystallization process(Ec = 34.6 kcal mol−1 for the firstpeaks and Ec = 41.6 kcal mol−1 for the second peaks) and the crystallization mechanism is characterized (kinetic exponentn = 2.09 for the firstpeaks, and n = 1.02 for the second peaks). The phases at which the alloy crystallizes after thethermal process have been identified by x-ray diffraction. The diffractogramof the transformed material indicates the presence of microcrystallites ofGeTe4 and AsTe, with an additional amorphous matrix remaining.