  Based on atomistic calculations of electron and phonon transport, we propose
to use surface decorated Silicon nanowires (SiNWs) for thermoelectric
applications. Two examples of surface decorations are studied to illustrate the
underlying deas: Nanotrees and alkyl functionalized SiNWs. For both systems we
find, (i) that the phonon conductance is significantly reduced compared to the
electronic conductance leading to high thermoelectric figure of merit, $ZT$,
and (ii) for ultra-thin wires surface decoration leads to significantly better
performance than surface disorder.
