Low-temperature electron mobility in a real δ-doped semiconductor

The low-temperature electron mobility in {δ}-doped GaAs is calculated by using the Boltzmann equation and the relaxation-time approximation. It is assumed that the electrons are scattered from ionized donors, which are spread uniformly throughout some distance. For donor-ion spreading of 50 to 100 {} the calculated mobilities, although still higher than experimental ones, are for some electron concentrations even 50% lower than those calculated assuming genuine {δ} doping. The possibility for the observation of such discontinuities which appear in the mobility when the Fermi level passes through the subband bottoms is discussed. {} 1996 The American Physical Society.