Thermoelectric Properties of Bi2Te2.7Se0.3 Solid Solution with Various Grain Sizes

摘要

The electrical conductivity (sigma) and the coefficients of thermal e.m.f. (alpha), Holl (R-H), and thermal conductivity (chi) of extruded n-Bi2Te2.7Se0.3 samples with various grain sizes are studied in the temperature range 77-300 K after extrusion and upon subsequent annealing. It is shown that annealing substantially increases sigma and chi and has a little effect on alpha at 77 K. This indicates that at 77 K, the structural imperfections of grains play the main role in the electron and phonon scattering. There is a correlation between the degree of texture and thermoelectric properties.