Lattice relaxation of InAs heteroepitaxy on GaAs

Single layers of InAs are grown on GaAs at different orientations by molecular beam epitaxy. They are evaluated by electron diffraction, supplemented by X-ray absorption and reflection measurements. The threshold in layer thickness for lattice relaxation is similar for both (100) and (100). The former, however, generally exhibits an extended transition region with details depending on the growth conditions, while such a transition is invariably abrupt in the latter situation. The (100) growth, in addition, retains the narrowly streaked diffraction patterns throughout the deposition in contrast to the (100) growth. These observations are attributed to different microscopic local atomic environments.