Thermoelectric properties of Sb-doped Mg2Si semiconductors

The thermoelectric properties of Sb-doped Mg2Si (Mg2Si:Sb = 1:x(0.001 ≦ x ≦ 0.02)) fabricated by spark plasma sintering have been characterized by Hall effect measurements at 300 K and by measurements of electrical resistivity (ρ), Seebeck coefficient (S), and thermal conductivity (κ) between 300 and 900 K. Sb-doped Mg2Si samples are n-type in the measured temperature range. The electron concentration of Sb-doped Mg2Si at 300 K ranges from 2.2 × 1019 for the Sb concentration, where x = 0.001, to 1.5 × 1020 cm−3 for x = 0.02. First-principles calculation revealed that Sb atoms are expected to be primarily located at the Si sites in Mg2Si. The electrical resistivity, Seebeck coefficient, and thermal conductivity are strongly affected by the Sb concentration. The sample x = 0.02 shows a maximum value of the figure of merit ZT, which is 0.56 at 862 K.