PREPARATION OF A HIGHLY ORDERED AU(111) PHASE ON A POLYCRYSTALLINE GOLD SUBSTRATE BY VACUUM DEPOSITION AND ITS CHARACTERIZATION BY XRD, GISXRD, STM/AFM, AND ELECTROCHEMICAL MEASUREMENTS

An atomically smooth, highly ordered Au (111) phase was obtained by vacuum deposition on a polycrystalline gold disk substrate followed by anneal-quenching treatment. The X-ray diffraction data showed that the intensity of a peak corresponding to the (111) orientation dominates, in the samples prepared as above, with other small peaks corresponding to orientations other than (111). Only a strong and sharp peak corresponding to the (111) surface phase was observed in the samples prepared as above in grazing incident surface X-ray diffraction measurements using synchrotron orbital radiation. These results indicate that only the (111) orientation existed at the surface of the sample. The monoatomic step lines with a crossing angle of 60 degrees, as expected for a surface with 3-fold symmetry, and the atomic arrangement of (111) orientation were observed by STM and AFM measurements, respectively. Electrochemical measurements confirmed the high quality of the surface orientation in the sample prepared as above, and the peak potentials corresponding to gold oxide formation and under potential deposition/desorption of copper are in good agreement with the values obtained at a Au (111) single-crystal electrode.