Properties of nanostructured one-dimensional and composite thermoelectric materials

Over a decade ago, Dresselhaus predicted that low-dimensional systems would one day serve as a route to enhanced thermoelectric performance. In this article, recent results in the thermoelectric properties of nanowires and nanotubes are discussed. Various synthesis techniques will be presented, including chemical vapor deposition for the growth of thermoelectric nanostructures in templated alumina. Electrical transport measurements of carbon nanostructures, such as resistivity and thermopower, have revealed some very interesting thermoelectric properties. Challenges still remain concerning the measurement of individual nanostructures such as nanowires. Much work has been performed on the thermoelectric properties of carbon nanotubes, and these results will be highlighted. In addition, routes for enhanced thermoelectric materials have focused on incorporating nanostructures within the bulk materials. The role of these "hybrid composite structures" based on nanomaterials incorporated into the bulk matrix and the potential for enhanced performance are discussed.