6533b828fe1ef96bd128784f

RESEARCH PRODUCT

Iron deposition on TiO2(110): effect of the surface stoichiometry and roughness

subject

description

Abstract Characterizations of ultra-thin iron films deposited on TiO 2 (110) surfaces with different stoichiometries, roughnesses and crystallinities have been carried out by X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). For a high initial roughness of the substrate, a 2D growth mode is observed up to three monolayers. But, if the initial roughness is low, clusters grow on the TiO 2 surface. Whatever the initial surface stoichiometry, electronic exchanges occur between titanium and iron leading to a reduction of titanium and an oxidation of iron. This interaction between iron and titanium dioxide surface takes place only at the interface between the metal and the oxide surface: during the completion of the first layer for deposition on a non-stoichiometric and rough surface (2D growth) and at the base and periphery of the islands for 3D growth (in the case of deposition on a flat and stoichiometric surface). Moreover, the amount of electrons exchanged between titanium and iron is lower when the substrate oxide surface is prereduced. The interaction between the deposited metal and the oxide surface is related to the amount of available oxygen.