Angle-resolved photoemission study of Cu on ZnO(1 0 1¯ 0); room temperature deposition and annealing effect

The valence electronic structures of the Cu-covered ZnO(1 0 1¯ 0) surfaces have been studied by angle-resolved photoemission spectroscopy utilizing synchrotron radiation. The coverage dependent change in the Cu valence band indicates the cluster formation of Cu at room temperature. The Cu 3d state forms a band with an energy dispersion, and the coverage dependence of the Cu 3d band structure suggests that the electronic structure of the Cu cluster is initially two-dimensional and turns to be three-dimensional at high coverages. The annealing effect on the morphology and the electronic structure of the Cu clusters is also examined and discussed.