GROWTH AND DISLOCATION ETCHING OF Sb0.2Bi1.8Te3 SINGLE CRYSTALS

Abstract

Sb 0.2 Bi 1.8 Te 3 single crystals have been grown by the zone melting and Bridgman–Stockbarger methods. The freezing interface temperature gradients of 90°C/cm and 45°C/cm, respectively, have been found to yield the best quality crytals obtainable at the growth rate of 0.35 cm/h. The crystals have been characterized by the powder XRD technique. The crystals grown by the zone melting method have been observed to exhibit certain typical features on their top free surfaces. A new dislocation etchant has been developed to give reproducible etch-pitting on the cleavage surface. Tests of this dislocation etchant have been carried out successfully and the etchant has been used to obtain dislocation density in the crystals.