In Situ Grazing Incidence X-ray Scattering Study of the Epitaxial Growth of Ag on MgO(001)

The growth of Ag on MgO(001) was investigated from sub monolayer up to 600 Å coverage. A new method for the preparation of very flat, clean and stoichiometric MgO(001) surfaces is described. The growth is found to be intrinsic, with negligible influence of surface defects. Twins appear at the very first stages of deposition while stacking faults form during the coalescence. A detailed mechanism is proposed for the elastic and plastic misfit relaxation processes. The introduction of a new dislocation within an island is, whatever its size, preceded by a strong deformation of its edges. Plastic relaxation is shown to be a continuous process that starts well before coalescence and the appearance of an interfacial dislocation network.