Thermoelectric Properties and Transport Mechanism of Pure and Bi‐Doped SiNWs‐Mg₂Si

Abstract

Through the use of nano-Si wires as additive, a significant improvement in the thermoelectric (TE) properties of Mg 2 Si is achieved. SiNWs-Mg 2 Si materials are prepared by a wet etching method followed by field activated pressure assisted synthesis (FAPAS). The results show that the presence of SiNWs successfully decouples the relationship between the electrical resistivity and the Seebeck coefficient of Mg 2 Si. The effect of doping with Bi is also investigated. The results show that the addition of Bi changed the scattering mechanism, and a zT value of 0.47 is determined at 800 K for Mg 2 Si 0.99 Bi 0.01 -0.005SiNWs. The presence of MgO as an impurity and its effect on zT are discussed.

Recent Progress in Multiphase Thermoelectric Materials

“…The maximum value obtained for the Seebeck coefficient at 973 K was −156 µV/K, with an electrical conductivity of ~4 × 10 4 S/m. Silicon-based materials, although not common in thermoelectricity, have also been shown to benefit from energy filtering [103][104][105][106][107][108][109][110]. For instance, heavily doped Si with B with nanoparticles of Si has shown an increased Seebeck coefficient and electrical conductivity in a particular range of dopant concentrations [111].…”