Thermoelectric crystals Bi2Te2.88Se0.12 undoped and doped by CdCl2 or CdBr2 impurities, fabricated and characterized by XRD and Hall effect

Growth of an oriented Bi40−xInxTe60 (x = 3, 7) thermoelectric material by seeding zone melting for the enhancement of chemical homogeneity

“…Bi 2 Te 3 -In 2 Te 3 , when prepared by Czochralski, Bridgman and zone melting methods, a pronounced composition gradient must form in the initial transient region before the steady state is established and solidification occurs with constant composition. [5][6][7][8][9][10][11] The final transient is associated with the solute pile-up in front of the growing interface that eventually will solidify with a higher concentration. The length L i of the initial transient region can be calculated according to 28…”

“…Possible methods for producing Bi 2 Te 3 -based materials include different varieties of directional solidification and powder sintering using milling, hot pressing and so on. [5][6][7][8][9][10][11] Such chemical inhomogeneity introduces a variation of the site occupancy in the grown crystal that entails locally less favorable thermoelectric properties or even transformation of the conductivity type from positive to negative along the growth direction of a bulk ingot, 10 which would lead to loss of the desired thermoelectric properties. zone melting, and Bridgman and Czochralski growth methods, can produce a thermoelectric material exhibiting better thermoelectric properties than its counterparts prepared by the other methods.…”

“…4 However, owing to convection instabilities in the melt and to the related inhomogeneous solute redistribution processes during crystal growth, chemical homogeneity in the Bi 2 Te 3 -based oriented material is not easy to accomplish. [5][6][7][8][9][10][11] Such chemical inhomogeneity introduces a variation of the site occupancy in the grown crystal that entails locally less favorable thermoelectric properties or even transformation of the conductivity type from positive to negative along the growth direction of a bulk ingot, 10 which would lead to loss of the desired thermoelectric properties.…”

Preparation and thermoelectric properties of iodine-doped Bi2Te3-Bi2Se3 solid solutions

“…Although the single crystals demonstrated excellent thermoelectric properties, the method used for unidirectional crystal-growth is time-consuming and exhibits poor mechanical performance along the cleavage plane [12]. Nonhomogeneity in the Se content was also observed due to difficulty controlling the Se content [13]. Venkatasubramanian et al [3] reported ZT = 1.4 for an n-type Bi 2 Te 3 /Bi 2 Te 2.7 Se 0.3 superlattice, but this structure has some limitations for thermoelectric applications [14].…”