Calorimetric studies of Al_xTe_100-x glasses: composition dependence of crystallization and a new compound in the Al-Te system

Abstract

Bulk, semiconducting Al_xTe_100-x glasses have been prepared by quenching from the melt. The thermal crystallization behaviour of these materials has been studied by differential scanning calorimetry. Al_xTe_100-x glasses with 15 ≤ x ≤ 23 have been found to exhibit a double glass transition and double stage crystallization on heating. Glasses with 28 ≥ x ≥ 25 show only a single glass transition and single stage crystallization. The observed cross-over in the thermal crystallization behaviour can be connected to rigidity percolation in the chalcogenide glasses. Further, the thermal annealing of Al_xTe_100-x glasses leads to a new phase φ (Al-Te), which is not the equilibrium crystalline phase Al₂Te₃ of the Al-Te system.