HIGH-RESOLUTION TRANSMISSION ELECTRON-MICROSCOPY STUDIES OF THE AG/MGO INTERFACE

Ag layers with a thickness of 100 nm were deposited on {100} MgO substrates by molecular beam epitaxy (MBE). The substrates were produced by cleaving MgO single crystals and subsequent annealing in ultra high vacuum. X-ray texture measurements indicate a preferential orientation of Ag {100} planes parallel to the {100} surface of the MgO substrate. The atomistic structure of the Ag/MgO interface was imaged by high resolution transmission electron microscopy (HRTEM). Lattice images of Ag and MgO in parallel orientation show structural defects and lattice strain at the Ag/MgO interface, which are introduced by the lattice mismatch of 3% between Ag and MgO. The atomic resolution images are compared with the computer-simulated lattice image of a model structure. Finally our atomistic model of the Ag/MgO interface, which includes a misfit dislocation network is discussed in connection with theoretically calculated interfacial energies.