Growth and thermoelectric properties of artificially layered (BiSb)/sub 2/Te/sub 3/

Abstract

We report that the layered structure of Bi/sub 2/Te/sub 3/-based materials can be prepared with layer-by-layer growth using MBE; i.e., we sequentially deposit Te and Bi monolayers according to the sequence of Bi/sub 2/Te/sub 3/. The sequence of the layered structure is Te-Bi-Te-Bi-Te and three such sequences make a unit cell with a total of 6 Bi layers and 9 Te layers. In bulk and thin film (BiSb)/sub 2/Te/sub 3/ prepared by co-deposition, Bi and Sb occupy lattice sites randomly. In order to engineer the electronic band structure to achieve better thermoelectric properties and/or reduce the lattice thermal conductivity by increasing phonon scattering at interfaces, we have prepared artificially ordered (BiSb)/sub 2/Te/sub 3/. We will discuss the growth and thermoelectric properties of artificially layered (BiSb)/sub 2/Te/sub 3/ thin films and compare their properties with conventional structures.