Thermoelectric transport calculation of Si nanoclusters with different geometric shapes

Fabricating small-sized Si nanoclusters has been considered as an effective approach to obtain a high figure-of-merit of thermoelectric materials. To reveal the electron and phonon transport in the Si nanoclusters with different geometric shapes, the electronic structure, the lattice dynamics and the thermoelectric properties of Si nanobox, Si nanocylinder, Si nanosphere and Si nanotetrahedron were investigated through first-principles calculation, lattice simulation and Boltzmann transport theory. The influences of the electronic structure and the lattice dynamics on the thermoelectric properties were also studied in detail. Therefore the work provides a complete understanding on the thermoelectric transport in the Si nanoclusters with different geometric shapes. Moreover, a largely enhanced figure-of-merit (ZT) at 1200 K of 1.70 has been achieved for Si nanobox.