Structural properties of MnAs epitaxial films on GaAs:: an in situ x-ray study

We present an analysis of the relaxation of thin MnAs films on GaAs(001) by x-ray grazing incidence diffraction during molecular beam epitaxy. Separate in-plane peaks of the MnAs layer and the GaAs substrate are detected for average thicknesses starting from approximate to 1 monolayer indicating the formation of a relaxed MnAs lattice. The variation of position of the MnAs peaks during growth yields the time dependence of relaxation. MnAs domains of different orientations are detected. A line broadening due to size and strain effects is observed. We find a regular arrangement of misfit dislocations at the interface. The range of twist of the domains reduces during growth indicating an improvement of the epitaxy.