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Abstract: In the present study, p-type (Bi2Te3) x (Sb2Te3)1− x crystals with various chemical compositions (, 0.05, 0.10, 0.16, 0.20, 0.24 and 0.26) were fabricated through the zone melting method. Thermoelectric properties, including Seebeck coefficient (), electrical conductivity () and thermal conductivity (), were measured in the temperature range of 300–500K. The influence of the variations of Bi2Te3 content () on the thermoelectric properties was studied. The increase of Bi2Te3 content () caused a decrease in hole concentration and thus a decrease of and an increase of . The maximum figure of merit () of 1.14 was obtained at about 350K for the composition of 24% Bi2Te3–76% Sb2Te3 with 3wt% excess Te. [Copyright &y& Elsevier]

Abstract: Two crystals of Bi2Se0.21Te2.79 doped with 0.08wt% TeI4 were grown by zone melting on the Foton-M3 spacecraft of Russia and the ground in 2007, respectively. The chemical composition, structure and thermoelectric properties of the space and ground crystals grown were evaluated by EPMA, XRD and thermoelectric measurements including Seebeck coefficient, electrical conductivity and thermal conductivity. The compositions of the space crystal grown along growth direction were more homogeneous than that of the ground crystal grown. The crystallization of space crystal grown was obviously improved. The maximum ZT value of space crystal reached 1.14 at 300K, which was higher about 29% than that of ground crystal at room temperature. These results imply that the composition homogeneity and crystallization of Bi2Se0.21Te2.79 crystal can be improved under microgravity conditions, which is helpful for enhancing thermoelectric figure of merit of Bi2Te3-base materials. [Copyright &y& Elsevier]