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 roo m temperature has been studied by X-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy. It is found that the Y-Cu com pound films are easily oxidized to form yttrium oxide at room temperat ure. The formed oxide prevents the Y atoms from diffusing into the top most surface. Valence band and core level photoelectron spectra indica te 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 temperat ure, and a uniform Y2O3 layer is formed on the Cu(100) surface.