THE DEVELOPMENT OF NICKEL ULTRA-THIN FILMS AND THE INTERACTION WITH OXYGEN ON THE SrTiO3(100) SURFACE STUDIED BY SOFT X-RAYS PHOTOELECTRON SPECTROSCOPY

Abstract

The electronic properties of very thin Ni films on the SrTiO 3(100)- Fe doped surfaces and their interaction with oxygen have been studied by soft X-rays photoelectron spectroscopy measurements. Nickel starts to become metallic on the surface in the very early adsorption stages. Oxygen adsorption on the nickel covered SrTiO 3(100) surface leads gradually to an almost complete oxidation of the nickel overlayer. The oxidation seems to take place through two different oxidation states, which according to the literature are due to the Ni 2+ and Ni 3+ species. The heating of the O / Ni / SrTiO 3 system at 850 K, causes a partial reduction of the nickel overlayer.