In situ photoemission study of the contact formation of (Ba,Sr)TiO3 with Cu and Au

The contact formation of (Ba,Sr)TiO3 thin films and SrTiO3 single crystals with Cu and Au have been studied using X-ray and ultraviolet photoelectron spectroscopy with in situ sample preparation. During metal deposition a partial reduction of the substrate occurs. The Fermi level at the interface is found to be close to the conduction band minimum, indicating small Schottky barrier heights (< 0.2 eV).