In situ investigation of MnAs/GaAs(001) growth and interface structure using synchrotron x-ray diffraction

Abstract

Using grazing-incidence synchrotron x-ray diffraction, we have quantitatively studied the strain evolution of epitaxial MnAs films in situ during growth by molecular-beam epitaxy. We find that the MnAs layer grows in four distinct stages, being compressively strained at the beginning of growth and relaxing as the thickness increases. The evolution of the in-plane grain size is determined as a function of layer thickness. We find a one-dimensional ordered array of periodic misfit dislocations at the interface, having a periodicity of 4.9±0.05 nm along GaAs[110]. An annealing of the film increases the grain size as well as improves the ordering of dislocation array.