The microstructures of bulk nanograined p-type bismuth antimony telluride with a thermoelectric dimensionless figure-of-merit ZT = 1.4 are investigated using transmission electron microscopy. It is found that the bulk material contains both nano- and microsized grains. Between the nanograms, bismuth-rich interface regions with a 4 nm thickness were detected. In addition, nanoprecipitates as well as other defects are also found to be embedded in the nanograms. The high ZT is attributed to the slight increase in the electrical conductivity, and to the large decrease of the thermal conductivity.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Condensed Matter Physics
- Mechanical Engineering