Effect of Sm-doping on microstructure and thermoelectric properties of textured n-type Bi₂Te₂.₇Se₀.₃ compound due to change in ionic bonding fraction

Abstract

Textured n-type Bi₂-xSmxTe₂.₇Se₀.₃ compounds with x ¼ 0; 0.005; 0.02 and 0.05 have been prepared by microwave-solvothermal synthesis of starting powders and spark plasma sintering of bulk materials. Texturing [001] axis coincided with direction of spark plasma sintering pressuring. With increasing x, (i) an average lateral size of grains in the samples is decreasing; (ii) the Lotgering factor characterizing a degree of preferential orientation of the grains is increasing; (iii) anomalies of all the thermoelectric properties, related to onset of intrinsic conductivity, are shifted to higher temperatures