Inhomogeneous lattice distortion in the heteroepitaxy of InAs on GaAs

Lattice relaxation in InAs epitaxial films, grown by molecular beam epitaxy on GaAs, has been studied by grazing-incidence x-ray diffraction, supplemented by in situ reflection electron diffraction. Inhomogeneous lattice distortion has been found in that the films consist of weakly and strongly strained regions, and the latter disappear with increasing film thickness. The (100) orientation is favored over the (110) in the formation of the strongly strained domains because of the relatively low elastic energies.