Abstract
To improve the conversion efficiency of thermoelectric device, segment type combination of different thermoelectric materials is very effective. However, it is necessary to consider the thermal stress when different materials are joined. So it has been suggested to join SiGe(high performance at 900-1200K) to PbTe(high performance at 600-900K) through the SiGe/PbTe FGM layers. We studied thermoelectric properties of each of SiGe/PbTe composites of the SiGe/PbTe FGM layers. The result is as follows. Electrical resistivity of the SiGe/PbTe composites in the present study was about 1000 times greater than that of SiGe or PbTe single phase. Therefore, the figure of merits of the SiGe/PbTe composites rather degraded compared to those for each single phase. This undesirable results were interpreted to be caused by the change of electronic structure at the interface of SiGe and PbTe with slight interdiffusion into each components.
