Theoretical studies on the thermoelectric figure of merit of nanograined bulk silicon

In this paper, we investigate the phonon transport in silicon nanocomposites using Monte Carlo simulations considering frequency-dependent phonon mean free paths, and combine the phonon modeling with electron modeling to predict the thermoelectric figure of merit (ZT) of silicon nanocomposites. The model shows that while grain interface scattering of phonons is negligible for large grain sizes around 200 nm, ZT can reach 1.0 at 1173 K if the grain size can be reduced to 10 nm. Our results show the potential of obtaining a high ZT in bulk silicon by the nanocomposite approach. (C) 2010 American Institute of Physics. [doi:10.1063/1.3478459]