TiCl4(THF)2 impregnation on a flat SiOx/Si(1 0 0) and on polycrystalline Au foil: determination of surface species using XPS

TiCl₄(THF)₂ was impregnated by spin-coating on a Si(1 0 0) wafer covered with a thin SiO_x layer and on a polycrystalline Au foil. The nature of the surface species was determined at room temperature and after annealing, by X-ray Photoelectron Spectroscopy (XPS) and Atomic Force Microscopy (AFM). A mixed Si:O:Ti interfacial layer was formed on the silicon substrate while in the case of Au, TiOCl_x and TiO_x were the main surface species at room temperature. Annealing at 723 K leads to the total desorption of the Cl atoms, and in both cases a significant amount of Ti atoms was reduced to the Ti³⁺ state. AFM measurements revealed a homogenous distribution of nano-sized TiO_x clusters with semi-ellipsoid shape and increased contact area with the underlying silica.