Bismuth telluride hexagonal nanoplatelets and their two-step epitaxial growth.

We report a synthesis of discrete, single-crystal, defect-free, and hexagonal Bi2Te3 nanoplatelets using a high-temperature organic solution approach, and we demonstrate a two-step epitaxial growth of the cylindrical strings of Bi2Te3 nanoplatelets on the surface of the Te rod by packing them along c-axis in a top-bottom-top-bottom sequence. This type of building-up provides additional opportunity for the exploration of novel thermoelectric properties from such quantum-confined materials, in which the boundary scattering of phonons is anticipated to enhance.