Formation of Al/CuO bilayer films: Basic mechanisms through density functional theory calculations

We carry out Density Functional Theory calculations of the initial steps of CuO deposition onto Al(111) surface and Al deposition onto CuO(11–1) surface to investigate the basic mechanisms responsible for the growth of Al/CuO interface. Chemical pathways for adsorption and incorporation into the subsurfaces are examined, and associated activation energies are determined. We demonstrate that Al does penetrate the CuO surface with subsequent amorphization of the CuO upper layer. In turn, CuO undergoes a dissociative adsorption onto Al(111), leading to isolated Cu and O atoms of which further penetration in the Al surface is detailed. While Cu pathway for subsurface penetration is characterized by a low activation barrier (0.5 eV), O interaction with the Al surface is much more complex; aluminum oxidation is shown to occur at a nominal oxygen coverage through a drastic rearrangement of the Al surface atoms.