Papers by Author: Shingo Tanaka

Abstract: Ab initio pseudopotential calculations of Cu/Al2O3 and Au/TiO2 interfaces have revealed strong effects of interface stoichiometry. About the Cu/Al2O3 system used for coatings and electronic devices, the interfacial bond of the O-terminated (O-rich) Cu/Al2O3(0001) interface is very strong with ionic and covalent Cu-O interactions, although that of the Al-terminated (stoichiometric) one is rather weak with electrostatic and Cu-Al hybridization interactions. About the Au/TiO2 system with unique catalytic activity, the adhesive energy between non-stoichiometric (Ti-rich or O-rich) TiO2(110) surface and a Au layer is very large, and there occur substantial charge transfer and orbital hybridization, which should have close relations to the catalytic activity.

Abstract: Interfacial atomic and electronic structures of Cu/Al2O3(0001) and Cu/Al2O3(11 ＿ ,20) prepared by a pulsed-laser deposition technique were characterized by high-resolution transmission electron microscopy (HRTEM) and electron energy-loss spectroscopy (EELS). It was found that both systems have O-terminated interfaces, irrespective of different substrate orientations. This indicates that Cu-O interactions across the interface play an important role for the Cu/Al2O3 systems.