  Electronic transport is theoretically investigated in laterally confined
semiconductor superlattices using the formalism of non-equilibrium Green's
functions. The transport properties are calculated for nanowire superlattices
of varying diameters, from the quantum dot superlattice regime to the quantum
well superlattice regime. Scattering processes due to electron-phonon
couplings, phonon anharmonicity, charged impurities, surface and interface
roughness and alloy disorder are included on a microscopic basis. Elastic
scattering mechanisms are treated in a partial coherent way beyond the
self-consistent Born approximation. The nature of transport along the
superlattice is shown to depend dramatically on the lateral dimensionality. In
the quantum wire regime, the electron velocity-field characteristics are
predicted to deviate strongly from the standard Esaki-Tsu form, with pronounced
current peaks due to integer and fractional resonances with optical phonons.
