ELECTRONIC-STRUCTURE OF SHORT-PERIOD N-P GAAS DOPING SUPERLATTICES

We present the electronic structure of compensated, noncompensated, and nonequilibrium uniformly doped short-period GaAs doping superlattices. Self-consistent calculations are described, which include miniband dispersion, and can be applied to arbitrarily shaped superlattice potentials. For n-p superlattices with periods less than 200 angstrom, we find significant dispersion in the first conduction subband and weak confinement of electrons to the donor layers. Band filling is shown to be the major contribution to the tunability of the electronic structure in these superlattices under excitation, while for periods greater than 200 angstrom, carrier screening of the superlattice potential dominates the variation. The calculated carrier-recombination lifetimes in short-period doping superlattices are comparable to bulk GaAs.