Thermoelectric Properties of β-SiC Fabricated from Rice Hulls in a Nitrogen Atmosphere

The thermoelectric properties of β-SiC fabricated from rice hulls was investigated by measuring the Seebeck coefficient (α), the electrical conductivity (σ) and the thermal conductivity (κ). The synthesized β-SiC showed n-type conductivity due to the doping of nitrogen into the structure. As the nitrogen pressure increased, the absolute value of the Seebeck coefficient decreased. The electrical conductivity was found to increase with nitrogen content up to about 0.35mass%, beyond which the value remained relatively constant. A power factor of 4×10-6W·m-1·K-2 and a thermal conductivity of about 8W·m-1·K-1 at 1000K resulted in a Z=0.055×10-3K-1 figure of merit.