  The thermoelectric properties of hybrid graphene-boron nitride nanoribbons
(BCNNRs) are investigated using the non-equilibrium Green's function (NEGF)
approach. We find that the thermoelectric figure of merit (ZT) can be
remarkably enhanced by periodically embedding hexagonal BN (h-BN) into graphene
nanoribbons (GNRs). Compared to pristine GNRs, the ZT for armchair-edged BCNNRs
with width index 3p+2 is enhanced up to 10~20 times while the ZT of nanoribbons
with other widths is enhanced just by 1.5~3 times. As for zigzag-edge
nanoribbons, the ZT is enhanced up to 2~3 times. This improvement comes from
the combined increase in the Seebeck coefficient and the reduction in the
thermal conductivity outweighing the decrease in the electrical conductance. In
addition, the effect of component ratio of h-BN on the thermoelectric transport
properties is discussed. These results qualify BCNNRs as a promising candidate
for building outstanding thermoelectric devices.
