Photoemission study on oxidation of the YCu intermetallic compound on Cu(100) surface

Oxidation of YCu intermetallic compound on the Cu(100) surface at room temperature has been studied by X-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy. It is found that the YCu compound films are easily oxidized to form ytrium oxide at room temperature. The formed oxide prevents the Y atoms from diffusing into the topmost surface. Valence band and core level photoelectron spectra indicate the presence of chemisorbed oxygen species (O−) which are formed on top of the yttrium oxide at high oxygen exposure. On annealing, the O− ions can react with metallic yttrium continuously at medium temperature, and a uniform Y2O3 layer is formed on the Cu(100) surface.