Preparation of p- and n-type SiC-based thermoelectric materials by spark plasma sintering

We report on the preparation of Si/sub 3/N/sub 4/ or Al/sub 4/C/sub 3/ added SiC by spark plasma sintering (SPS) and their thermoelectric properties. The relative densities of all the sintered materials were more than 80% of the theoretical value. The conduction types were controlled by the addition of Si/sub 3/N/sub 4/ for n-type and Al/sub 4/C/sub 3/ for p-type. The electrical resistivity decreased and the Seebeck coefficient increased with temperature. We also found that the power factor depends on the composition of the Si/sub 3/N/sub 4/ or Al/sub 4/C/sub 3/ and takes the maximum value at 7wt% addition at 973K.