Self-assembled nanometer lamellae of thermoelectric PbTe and Sb2Te3 with epitaxy-like interfaces

Utilizing the decomposition of metastable Pb2Sb6Te11 into PbTe and Sb2Te3, we produced a layered (lamellar) microstructure of PbTe and Sb2Te3 in which the interlamellar spacing can be controlled by the temperature and time of the decomposition process. Adjacent PbTe and Sb2Te3 lamellae are crystallographically oriented, indicating high-quality epitaxy-like interfaces. Average lamellar spacings as small as 180 nm are observed, corresponding to a PbTe layer thickness of 40 nm. These nanoscale multilayers, formed by bulk processing, resemble thin-film superlattice thermoelectric materials, which have shown exceptionally high thermoelectric efficiency.