Thermal conductivity of bismuth telluride nanowire array-epoxy composite

Abstract

Electrodeposition of nanowire array in porous anodic alumina (PAA) templates combine the performance benefits offered by crystallographic texture control, lattice thermal conductivity suppression through boundary scattering of phonons, elastic relaxation of misfit strain, and scalablity essential for high efficiency thermoelectric devices. The template material, however, can serve as a thermal shunt thereby reducing the effective thermoelectric performance. Here, we demonstrate a process of minimizing the parasitic thermal conduction by replacing the PAA matrix with SU-8 (κ∼0.2 W/m K). We report a reduction in the performance penalty from 27% for Bi2Te3/PAA to ∼5% for Bi2Te3/SU-8 nanocomposite by thermal conductivity measurements using a photoacoustic technique.