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

The scattering of carriers in a two-dimensional electron gas (2DEG) in a series of novel GaAs/n-AlGaAs heterojunctions is studied for the case where InAlAs anti-dots are embedded near the channel. Mobilities μ are measured as functions of the electron concentrations N_e and are compared with theoretical models which take into account the shape and distribution of anti-dots. In samples with low dot densities, mobilities are well explained in terms 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 roughness-like potential with Gaussian-type correlation is shown to account for the data. Influences of growth conditions and the alloy composition on the diameter and the density of InAlAs dots are also discussed.