P-Type(Bi0.25 Sb0.75)2Te3 Thermoelectric Element Fabrication And Characterization

Author(s): Ghassem Kavei

Bi2Te3 based solid solutions, are widely utilized as thermoelectric(TE) materials in peltier modules, in order to attain higher figure of merit(Z) a fraction of weight at different percentage of Sb is added. The compound Bi-Te-Sb prepared by unidirectional solidification techniques such as melting accompanied with oscillating the melted compound followed by, crystallizing by zone growth method. This work is focused on, the preparation and characterization of the samples with formula Bi2Te3 and(Bi0.25 Sb0.75)2 Te3.(Bi0.25 Sb0.75)2 Te3 are known as p-type TE pellet, this compound has a higher Z compared with other solid solutions of the Sb-Bi , which have been tested as p-type pellet. The major aspects of TE such as electrical and thermal conductivities and seebeck coefficient, which directly affect the figure of merit were measured. X-ray powder diffraction analysis of(Bi0.25 Sb0.75)2 Te3 compared with Bi2Te3 suggests that the grown crystals are stoichiometric for(Bi0.25 Sb0.75)2 Te3. It should also be noted that there is a strong relation between Z, balancing charge carriers and phonons of the compound, but they will not be discussed here. From experimental results Z2.710-3K-1 was obtained, this is the same value which was reported in the previous work.

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