A full theory of thermoelectric transport in superlattices, including
the well width and energy dependence of the optical and acoustic phono
n scattering and the effects of confinement in raising valley degenera
cy is developed. It is shown that these features result in qualitative
ly significant modifications in the predicted figure of merit of super
lattice systems. Results are given for PbTe superlattices, and comment
s are made on recent experimental results for such systems. (C) 1997 A
merican Institute of Physics.