  Some of the most promising candidates for next generation thermoelectrics are
nanocomposites due to their low thermal conductivities that result from phonon
scattering on the boundaries of the various material phases. However, in order
to maximize the figure of merit ZT, it is important to understand the impact of
such features on the thermoelectric power factor. In this work we consider the
effect that nanoinclusions and voids have on the electronic and thermoelectric
coefficients of two dimensional geometries using the fully quantum mechanical
Non Equilibrium Greens Function method. This method combines in a unified
approach the details of geometry, electron phonon interactions, quantisation,
tunnelling, and the ballistic to diffusive nature of transport. We show that as
long as the barrier height is low nanoinclusions can have a positive impact on
the Seebeck coefficient and the power factor is not severely impacted by a
reduction in conductance. The power factor is also shown to be approximately
independent of nanoinclusion and void density in the ballistic case. On the
other hand, in the presence of phonon scattering voids degrade the power factor
and their influence increases with density.
