Scattering of 2D electrons by self-organized anti-dots in n-AlGaAs/GaAs heterojunction channels

The scattering of carriers ill a two-dimensional electron gas (2DEG) in a s eries of novel GaAs/ n-AlGaAs heterojunctions is studied fur the case where InAlAs anti-dots are embedded near the channel. Mobilities mu are measured as functions of the electron concentrations Nr and are compared with theor etical models which take into account the shape and distribution of anti-do ts. In samples with low dot densities! mobilities are well explained in ter ms of the scattering by anti-dots with a random distribution. In contrast, in samples with dense and overlapping dots and a thick wetting layer, a tou ghness-like potential with Gaussian-type correlation is shown to account fo r the data. Influences of growth conditions and the alloy composition on th e diameter and the density of InAlAs dots are. also discussed.