Anisotropic scattering of elongated GaSb/GaAs quantum dots embedded near two-dimensional electron gas

Elongated GaSb/GaAs quantum dots (QDs) with a lateral aspect ratio of 2~3 is synthesized by the molecular beam epitaxy (MBE) with carefully controlling the Sb₄ beam flux and As₄ background pressure. These self-assembled quantum dots having geometrical anisotropy are embedded in the vicinity of the two-dimensional electron gas (2DEG). Anisotropic hall mobilities of the 2DEG under the helium temperature transport measurements were confirmed. The mobility in the [110] direction is larger than that in the [1-10] direction. It is believed that this mobility difference is due to the anisotropic scattering potential of the GaSb/GaAs QDs owing to their large geometrical anisotropy. Under constant potential model of square barrier, we proved these anisotropic quantum dots show larger scattering cross-section in the [1-10] direction than in the [110] direction for transporting electrons.