Bi2Te3/Sb2Te3 Superlattice Structures for High-ZT Thermoelectric Cooling Devices

摘要

The goal of this project is to demonstrate factorial improvement in thethermoelectric figure of merit (ZT) with thin film Bi2Te3/Sb2Te3 superlattice (SL) structures compared to state of the art bulk Bi(2-x)Sb(x)Te3 alloys for high performance thermoelectric devices. The motivation for the use of SL structures has been the hypothesis that the atomic size and mass differences at the SL interfaces as well as the periodic SL structure result in enhanced phonon scattering leading to a reduction in lattice thermal conductivity. The SL structures, consisting of pure Bi2Te3 and Sb2Te3 materials, are also expected to offer higher electrical conductivities compared to alloyed materials through reduced alloy scattering of carriers and therefore larger carrier mobilities. With a successful demonstration of the enhancement in the thermoelectric properties of the Bi2Te3/Sb2Te3 SL structures, another objective would be to address specific issues related to the development of a viable thin film thermoelectric device technology.