Modeling the Thermoelectric Properties of Nanocomposites

Modeling the thermoelectric properties of nanocomposites is difficult due to the complex grain boundary scattering processes which scatter both electrons and phonons. In this work we describe a code we developed which numerically calculates the electrical and thermal properties of bulk and nanocomposite thermoelectric materials using the Boltzmann equation under the relaxation time approximation. The code is capable of calculating all the relevant thermoelectric properties over a wide range of temperatures, doping concentrations, and compositions, allowing for a full characterization of the material. We model nanocomposites by incorporating a grain boundary scattering rate based on a simple model we developed and models in the literature. The code and grain boundary scattering models are validated on bulk data and data from nano-SiGe, and are then applied to other candidate thermoelectric materials to see if they would be good candidates for nanocomposites. The analysis shows that GaAs might be promising as a nanocomposite thermoelectric material.