A METHOD FOR EVALUATING STRUCTURAL AND CHEMICAL INHOMOGENEITY IN COARSE-GRAINED INGOTS OF TERNARY BI-SB-TE SOLID-SOLUTIONS

Coarse-grained ingots of ternary solid solutions of composition Bi0.5S b1.5Te3 + 5 wt % Te with the p-type conductivity are studied. The ingo ts were grown by vertical zone melting, with annealing for 140 hours a t 380-400 degrees C. A set of experimental techniques is proposed for the characterization of the microstructure and the homogeneity of the ingots including X-ray diffraction, optical metallographic in polarize d light, microhardness and reflectivity measurements, and X-ray spectr al microprobe analysis. These techniques are used for estimating the e ffect of the growth conditions and subsequent thermal treatment on the characteristics of the materials under study.