Production and thermoelectric properties of sintered FeSi₂ Semiconductor

Abstract

Iron disilici de FeSi₂ is the most hopeful Thermoelectric Semiconductor, because both the components Fe and Si are deposited in plenty, the thermoelectric properties of FeSi₂ devices can readily be designed by controlled doping, and so on. Sintered bodies of Fe_1-xMn_xSi₂ (0≤x≤0.10) and Fe_1-yCo_ySi₂ (0≤y≤0.10) were prepared by the ceramic techniques, which are suitable for mass-production, and the roasting, sintering and annealing conditions in the sintering were investigated. For completely semiconducting specimens, the resistivity ρ and thermoelectric power Q were measured in the temperature range from 100 to 1400K in an argon atmosphere. The electrical resistivity ρ of Fe_1-xMn_xSi₂ (x=0.03 and x=0.06) indicated the relationship ρ=ρ_oexp[(E_a+E_h)/(kT)] in the temperature range from 150 to 600K, where E_a and E_h are the activation energy of the acceptor and the hopping energy, respectively. The Hall mobility μ_H showed the relationship μ_H=μ_oexp[-E_h/(kT)] in the temperature range from 150 to 250K. The electrical conduction mechanism of Fe_1-xMn_xSi₂ is qualitatively explained on the basis of the small polaron model.