Structural properties of Cu clusters on the O-terminated ZnO surface

We have studied the growth of Cu deposited by molecular beam epitaxy at room temperature on the O-terminated ZnO (0 0 0 1 ̄ ) surface. The structural properties of Cu on ZnO were investigated by X-ray scattering, atomic force microscopy (AFM) and scanning electron microscopy (SEM). Chemical characterisation was performed by X-ray photoemission spectroscopy (XPS). X-ray diffraction studies reveal a predominant (1 1 1) out-of plane texture and the [1 1 ̄ 0] Cu | |[1 1 2 ̄ 0] ZnO and [1 1 2 ̄ ] Cu | |[1 0 1 ̄ 0] ZnO azimuthal orientation of the Cu. The XPS spectra show that the ZnO (0 0 0 1 ̄ ) surface is completely covered after a Cu deposition with a nominal thickness of 50 Å. AFM and SEM images clearly indicate that at later deposition states Cu clusters increase laterally and later coalesce.