Preparation and Thermoelectric Properties of Mg₂Si_1−xGe_x (x=0.0∼0.4) Solid Solution Semiconductors

Abstract

Mg₂Si_1−xGe_x Solid Solution Semiconductors were prepared in the composition range 0.0≤x≤0.4. At a composition x=0.4, effects of impurities were investigated for dopants of Sb and Ag. Carrier concentrations were controlled up to 1.5×10²⁶ electrons/m³ and 5.5×10²⁵ holes/m³ by doping Sb and Ag, respectively. The thermal conductivity κ was measured at 300 K. By calculating the electronic thermal conductivity κ_el based on the Fermi integration, the lattice thermal conductivity κ_ph was estimated to be 2.10 Wm⁻¹ K⁻¹. Figure-of-merits Z’s of Mg₂Si_0.6Ge_0.4 at 300 K were 0.69×10⁻³ K⁻¹ for the n-type sample with an electron concentration of 5.4×10²⁵ m⁻³ (3000 ppmSb) and 0.47×10⁻³ K⁻¹ for the p-type one with a hole concentration of 5.2×10²⁵ m⁻³ (16000 ppmAg).