Scattering of two-dimensional electrons by self-assembled InAlAs anti-dots in novel n-AlGaAs/GaAs heterojunctions

Transport properties of a two-dimensional electron gas (2DEG) have been investigated in a novel selectively doped n-AlGaAs/GaAs heterojunction where InAlAs anti-dots are embedded in the vicinity of its channel. Electron mobilities and Shubnikov de Haas oscillations were measured and analyzed to determine the transport lifetime τt and quantum lifetime τq of the 2DEG. It is found that the ratio τt/τq is in the range of 3.5-5, which suggests that the dominant scattering mechanism has a character that is intermediate between an impurity scattering and a surface roughness scattering. Measured data are compared with a theoretical model and well explained by assuming that anti-dots give rise to a potential fluctuation with Gaussian-type correlation originating from the band off set at the dot-matrix boundary.