Faceting of homoepitaxial MgO(1 1 0) layers prepared by electron beam evaporation

Homoepitaxial layers of MgO(1 1 0) were deposited by electron beam evaporation, and their surface structure was examined by atomic force microscopy (AFM) and reflection high-energy electron diffraction (RHEED). The surface was faceted with {1 0 0} planes when the substrate temperature during the deposition was higher than 500 °C, while the surface was almost flat when the layers were deposited at 300 °C. A regular ridge-and-valley structure, with spacing of 24 nm, was obtained when the film was grown at 700 °C. The highly mobile admolecules played a central role on the formation of the ridge-and-valley structure faceted by equilibrium {1 0 0} planes.