Fabrication of 3D Nanostructured Bi-Sb-Te via Proximity field Nanopatterning for Thermoelectric Application

Abstract

The realization of independently controlling the electrical conductivity and the thermal conductivity has been a goal in thermoelectric field. Selectively controlling the electrical conductivity and the thermal conductivity has been one of the challenging problems because of interdependency of those properties by Widemann-Franz law. Here, we report the freestanding three-dimensional nanostructured Bismuth Antimony Telluride(3D BST) that accomplish this outcome. The thermal conductivity of 3D nanostructured BST was measured to ~ 1 W/mK at 300 K deriving from scattering of phonons with long mean free path(200 nm ~ 1 μm) resulting from its size effect. Meanwhile, the electrical conductivity and the seebeck coefficient of 3D nanostructured BST was preserved to the levels of film because electrons have short mean free path compared to its structure size. We suggest that 3D nanostructured thermoelectric materials are new and advanced way to overcome the limitation of closely related thermoelectric parameters.