Growth properties and structural analysis of ZnO films and of Au clusters on ZnO

We have studied the possibility to grow O-terminated ZnO(0001) films on Al2O3 substrates with high epitaxial quality. After growth via sputtering methods, the ZnO films were annealed to increase the film quality resulting in a mosaicity of 0.60degrees and a surface roughness of <3 Angstrom. Finally, gold films were sputtered at room temperature on the surface. The structural properties of the samples were investigated by X-ray scattering, reflection high-energy electron diffraction (RHEED) and by atomic force microscopy (AFM). AFM images clearly demonstrate that gold films with a nominal thickness of <50 Angstrom form clusters, which can be as high as 300 Angstrom. X-ray diffraction (XRD) studies reveal a predominant (111) texture of the clusters. Further deposition of Au leads to coalescing clusters smoothing out the surface. (C) 2002 Elsevier Science B.V. All rights reserved.