Influence of miniband electron elastic scattering on Bloch gain in semiconductor superlattices

Applying a three-dimensional Monte Carlo technique we simulated the motion of electrons subject to static and terahertz (THz) fields in semiconductor superlattices of different miniband widths at 4 K. We assumed electrons to be scattered at polar optic and acoustic phonons, and ionized impurities. We found that impurity scattering of electrons in the superlattice with the miniband width smaller than the optic phonon energy extends significantly a frequency range with a strong Bloch gain.