GROWTH OF ULTRATHIN AU AND AG FILMS ON A MODIFIED RU SURFACE

Using TDS, LEED and AES we have studied the adsorption of Ag and Au on an oxygen precovered Ru(001) surface in comparison with the growth mechanisms of these adsorbates on the non-modified substrate. Oxygen desorbs from Ru at higher temperatures than Ag and causes even the smallest detectable Ag coverage to sublimate like bulk silver (in contrast to the layer-by-layer growth on pure Ru). In turn, the TD-spectrum of Au is hardly affected because oxygen desorbs partially before gold. However, a quantitative analysis of AES intensities, taken at room temperature, as well as simple model calculations support a 3D island growth mode of Au on the oxygen precovered Ru surface as well. © 1990.