Stacking fault in Bi₂Te₃ and Sb₂Te ₃ single crystals

The structural characterizations of the Bi₂Te₃ and Sb₂Te₃ single crystals grown by the Zone melting method have been carried out by XRD and Chemical Etching process. The top free surface of as-grown Bi₂Te₃ and Sb₂Te₃ single crystal were observed under optical microscope. The particle size was calculated for a number of reflections using Scherrer's formula by X-ray diffraction method. By the use of XRD data, the growth and deformation fault probability has been estimated for the grown single crystals. The presence of stacking fault in the lattice structure of the grown crystals was verified by the probability of growth and dislocation fault. Also new dislocation etchant has been developed by the successive trialerror method. Dislocation etching was achieved on (1 1 1) crystal plane examined using a saturated solution of citric acid and nitric acid as the etchant. The dislocation etchant has been found to give reproducible etch pits on the cleavage surface for an appropriate etching time 30 s. The use of citric acid and nitric acid proved to be especially advantageous for the basal plane, producing etched pits suitable for dislocation etch pit counting.