This manuscript describes harmonic generation in semiconductor superlattices, starting from a
Nonequilibrium Green's functions input to relaxation rate-type analytical approximations for the
Boltzmann Equation in which imperfections in the structure lead to asymmetric current flow and
scattering processes under forward and reverse bias. The resulting current-voltage curves and the
predicted consequences on harmonic generation, notably the development of even harmonics are in
good agreement with experiments. Significant output for frequencies close to 1 THz (7th harmonic)
at room temperature, after excitation by a 141 GHz input signal, demonstrate the potential of
superlattice devices for GHz-THz applications
