Anisotropic screening and ionized impurity scattering in semiconductor superlattices and multiple quantum wells

摘要

We present a general theoretical treatment of ionized impurity scattering in semiconductor superlattices. Employing an extension of the quasihyphen;twohyphen;dimensional calculations of Stern and Howard to multihyphen;well structures, we explicitly account for nonuniformity of the wavefunction distribution function, arbitrary dispersion relations, scattering by impurities in neighboring periods, and screening by electrons in neighboring wells. Interperiod phenomena are found to be quite significant whenever the screening length is comparable to or longer than the distance between the quantum wells. Calculated results are compared with recent data for modulationhyphen;doped and setbackhyphen;modulationhyphen;doped HgTehyphen;CdTe superlattices. However, the discussion emphasizes general aspects of the problem rather than features specific to a particular system.