Temperature and porosity dependence of the thermoelectric properties of SiC/Ag sintered materials

Abstract

We have studied the thermoelectric properties of a SiC-based thermoelectric semiconductor with Ag and polysilastylene (PSS) as a dopant and as a sintering additive, respectively. Ag is an effective dopant to decrease the electrical resistivity of the SiC-based p-type thermoelectric semiconductor. It introduces carrier (hole) concentration 103−104 times larger than the case of Al-doped SiC with the typical doping concentration. PSS can control the sample density, which is one of the important factors in decreasing the electrical resistivity and thermal conductivity of the sintered samples. The figure of merit of the sample with Ag 2.0 wt% and PSS 0.1 wt% was estimated to reach 4 × 10−4 K−1 at 700 °C. This value implies that the SiC/Ag system is one of the promising thermoelectric materials for a high-temperature region.