Enhancement of Thermoelectric Efficiency in PbTe by Distortion of the Electronic Density of States

Abstract

Materials and Methods 1. Sample preparation method Tl-doped PbTe was made by direct reaction of appropriate amounts of Pb, Te, and Tl 2 Te in a fused-silica tube sealed under a vacuum. Each sample was briefly melted at 1273 K for 24 h and lightly shaken to ensure homogeneity of the liquid, then furnace cooled to 800 K and annealed for 1 week. The obtained ingot was crushed into fine powder and hot-pressed at 803 K for 2 hours under a flowing 4% H 2-Ar atmosphere. The final form of each polycrystalline sample was a 2mm thick disk about 10 mm in diameter. Phase purity was checked by powder X-ray diffraction. No impurity phases were found in the XRD patterns, indicating that all added Tl was dissolved in PbTe. The purities of all starting materials were at least 99.99%. The samples were stable in air at room temperature.

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