Electrical anisotropy of heteroepitaxial InSb/GaAs layers

We report on study of electrical and structural properties of InSb/GaAs(001) heteroepitaxial layers in [110] and [1-10] crystallographic directions. Strong anisotropy of electron transport parameters measured at a low magnetic field has been found, whereas the electrical transport through the InSb bulk layer studied by Shubnikov-de Haas oscillations is shown to be independent of the crystallographic directions. The low-field electrical anisotropy of the InSb films appears to be governed by two competitive anisotropic effects: influence of spontaneously formed In nanoclusters inhomogeneously distributed within the InSb layers and conductivity through the near-interface layer with high anisotropic density of extended defects.