Improved Thermoelectrics Based on Bismuth and Antimony Chalcogenides for Temperatures below 240 K

Abstract

Thermoelectric and galvanomagnetic properties for solid solution based on bismuth and antimony chalcogenides were studied for the optimal compositions and carrier concentrations in the temperature interval 100-240 K. Galvanomagnetic properties were analyzed in the framework of the many–valley energy spectrum model with isotropic and anisotropic scattering of charge carries. The figure-of-merit is shown to be determined with optimal relations between the values of the density-of-states effective mass, the carrier mobility taking into account degeneration of charge carriers, and the lattice thermal conductivity. The figure-of-merit also depends on anisotropy of the constant energy surface and scattering mechanism. Average values of the figure-of-merit <Z> through the temperature interval 100-240 K are equal to (2.5-2.65) 10-3 K1 for optimal compositions and carrier concentrations.