Using grazing incidence X-ray diffraction, a study was made of the evolution of strain, morphology and interfacial structure during growth at 250C and of the subsequent in situ annealing of MnAs films on GaAs. The MnAs film grew via the formation of relaxed islands which increased in size and finally coalesced to form a continuous film. An ordered array of misfit dislocations formed early at the interface, with a spacing of 4.95nm, releasing the misfit strain. The Burgers vector of the dislocations lay in the interface plane, and the inhomogeneous strain due to the dislocations was confined to a 1.6nm-thick region near to the interface. Annealing enhanced the order of the dislocation array and reduced the mosaicity of the MnAs layer. On MnAs/GaAs(113)A, the same mismatch was released by dislocations with a 2-times smaller Burgers vector and a 2-times smaller spacing, as compared with MnAs/GaAs(001).

Periodic Array of Misfit Dislocations at the MnAs/GaAs Interface Studied by Synchrotron X-Ray Diffraction. D.K.Satapathy, V.M.Kaganer, B.Jenichen, W.Braun, L.Däweritz, K.H.Ploog: Physical Review B, 2005, 72[15], 155303 (9pp)