Microengineered Bi₂Te₃composites for room temperature thermoelectric applications

T.E. Huber¹, A. Nikolaeva², A.Gitsu², L. Konopko²

¹Howard University,Washington, DC 20059, USA

² Institute of Solid StatePhysics, Academy of Sciences, Moldova

Semiconductor quantum wires constitute a promising thermoelectricmaterial because of the increase of the electronic density of states in low dimensionalmaterials. The thermoelectric figure of merit of these composites can beenhanced by an increase of the electrical to thermal conductivity ratio and,also, by the enhancement of the thermoelectric power that has been predicted tooccur for quantum wires of diameter d <~10 nm. We havesynthesized two types of Bi₂ Te₃ nanostructures: i)Arrays of 200-nm and 30-nm diameter wires in nanochannel anodic alumina and ii)Networks of 6-nm diameter bismuth telluride wires in porous Vycor glass. The composites are prepared byhigh pressure injection of the conducting melt. We discuss the characterizationand structural properties. We have found that the 200-nm and 30-nm wire’scrystallites are oriented with the basal plane perpendicular to the wire axis.The electronic transport properties and the thermoelectric power of thesecomposites will be discussed also.

This work has been supported by the U.S. National Science Foundationand the US-Moldova Civilian Research Development Foundation.