Misfit dislocations in a thin MgO/Mo(001) film were investigated by conductance and light-emission spectroscopy using scanning tunnelling microscopy and electron-paramagnetic resonance spectroscopy. The line defects exhibited a higher work function than the pristine MgO, being explained by their ability to trap electrons. The electron traps were associated with a nonstoichiometric defect composition in thin oxide films and attractive pockets in the Madelung potential in thicker ones. The latter traps could be reproducibly filled by the adsorption of atomic hydrogen, which gave rise to a free-electron-like signal in electron-paramagnetic resonance spectroscopy.

Electron Trapping in Misfit Dislocations of MgO Thin Films. H.M.Benia, P.Myrach, A.Gonchar, T.Risse, N.Nilius, H.J.Freund: Physical Review B, 2010, 81[24], 241415