ABSTRACT
Nanostructured thermoelectric (TE) materials have become an active research field recently to overcome
the efficiency barrier limiting the applications of conventional bulk TE materials. The conversion
efficiency of a TE device is represented by the dimensionless figure-of-merit ZT ¼ Ta
s=k; where T is the
absolute temperature, a is the Seebeck coefficient, s and k are the electrical and thermal conductivity,
respectively, of the TE material. Theoretical calculations of low-dimensional TE materials have predicted
a significant enhancement in ZT as the film thickness in two-dimensional (2D) systems
or the wire
diameter in one-dimensional (1D) systems
is decreased. These structures are benefiting from enhanced
carrier and enhanced phonon scattering at the boundaries. In the last decade, the preparations and
properties of low-dimensional TE materials have been intensively investigated, especially those of
superlattice thin films
and nanowire arrays.
