Anisotropy of the Seebeck coefficient in Czochralski grown p-type SiGe single crystal

To discuss the possibility of improvement in thermoelectric properties of SiGe alloys, we examined anisotropy of the Seebeck coefficient of the p-type SiGe single crystals with orientation of 〈1 1 1〉 and 〈1 0 0〉 grown by Czochralski method. For measurement of the Seebeck coefficient, we developed an apparatus that is capable of measuring the Seebeck coefficient in the temperature range of 300–900 K. The Seebeck coefficient of the sample with 〈1 1 1〉 orientation was around 325–400 μV/K, while that of the sample with 〈1 0 0〉 orientation was around 450–530 μV/K. The difference was larger than experimental error, and appeared to attribute to the difference in crystallographic direction.