Increase in the thermoelectric power produced by mechanically alloyed Pb < inf> 1-x Sn < inf> x Te due to the presence of 15 nm SnO < inf> 2 inclusions

Document Type

Article

Publication Date

10-15-2011

Abstract

Evidence is presented that 15 nm diameter SnO2 inclusions comprising approximately 2 vol. of bulk mechanically alloyed n-type Pb 1-x SnxTe (when x 7 and 27) significantly increase the electrical power produced by the material when it is doped above 1019cm-3 range. The experimentally measured temperature dependence of the electrical conductivity and Seebeck coefficient of Pb 0.93 Sn0.07 Te doped to 1.2 × 1019cm-3 and Pb0.73 Sn 0.27 Te doped to 3.8 × 1018cm -3 are shown to be consistent with those calculated in the framework of the Boltzmann transport equations using the relaxation time approximation and a three-band model for which the materials-specific constants are taken from published literature. The SnO2 inclusions are shown to impact the transport coefficients by changing the energy dependence and magnitude of the relaxation time due to the charge carrier scattering by a collection of inclusions in a geometry consistent with analysis of the x-ray diffraction data. Analysis of the experimental data shows that Pb0.93 Sn0.07 Te doped to 1.2 × 1019cm -3 generates more power than would a material without the 2 vol. of 15 nm SnO2 inclusions. Calculations using the experimentally validated model show that for carrier concentrations greater than 1 × 1019cm-3, the presence of these inclusions increases the power factor of both alloys in the 300-700 K temperature range. © 2011 American Institute of Physics.

Publication Title

Journal of Applied Physics

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