Microstructures and Thermal Properties of Water Quenched Thermoelectric Material in Bi2Te3-PbTe System

In order to design nano structured materials with enhanced thermoelectric properties, the alloys in the pseudo-binary Bi2Te3-PbTe system are investigated for their micro structure properties. For this synthesis, the liquid alloys are cooled by the water quenching method. Micro structure images are obtained by using an electron probe micro analyzer(EPMA). Dendritic and lamellar structures are clearly observed with the variation in the composition ratio between Bi2Te3 and PbTe. The increase in the Bi2Te3 composition ratio causes to change of the structure from dendritic to lamellar. The Seebeck coefficient of sample 5, in which the mixture rate of Bi2Te3 is 83%, is measured as the highest value. In contrast, the others decrease with the increase of the Bi2Te3 composition ratio. Meanwhile, p-type characteristics are observed in sample 6, at 91%-Bi2Te3 mixture rate. The power factors of the all samples are calculated with the Seebeck coefficient and resistivity.