Strain profiles in overcritical (001) ZnSe GaAs heteroepitaxial layers

ZnSe layers of various thicknesses have been grown epitaxially on (001)-ori ented GaAs substrates by metalorganic vapor phase epitaxy and studied by x- ray diffraction and Raman scattering. Consistent results have been found fo r the in-plane strains of both, ZnSe layers below and above the critical va lue of plastic relaxation. The experimental results are well described by s train profiles which are evaluated by an energy model and a geometrical mod el including the effects of strain and work hardening. The thickness-depend ent full widths at half maximum of the x-ray reflections and the Raman reso nances are accounted for by assuming uncorrelated misfit dislocations in th e layers. (C) 1999 American Institute of Physics. [S0021-8979(99)00813-0].