ANALYSIS OF THE GROWTH-PROCESS OF COBALT ON GOLD-(111) BY PHOTOEMISSION SPECTROSCOPY

we have analysed by means of synchrotron radiation induced angle resol ved photoemission spectroscopy (PES) and Auger electron spectroscopy ( AES) the growth of Cobalt layers deposited at room temperature on a Au (111) surface. We have studied the behaviour of the Au 4f (7/2) photoe mission lines (bulk peak at 84 eV, surface peak at 83.65 eV in binding energy) and Auger transitions (Au NW at 69 eV, Co MW at 53 eV). The a nalysis of the Au 4f (7/2) photoemission core level, for several thick nesses, shows core level shifts corresponding to different environment s for the Au atoms. From the evolution of the positions and intensitie s of the different contributions of Au 4f (7/2) line, three stages in the growth of Co on Au (111) can be deduced. Up until 1 monolayer (ML) of Co deposited, we observe a regular attenuation of the surface line corresponding to a three-dimensional growth : only half of the surfac e is covered. Between 1 and 2 ML, the uncovered surface does not chang e : the height of the islands increases. Above 2 ML; the coalescence o f islands starts and a third component appears in the photoemission li ne at a binding energy of 84.4 eV which can be attributed to an interd iffusion between the Co overlayer and the Au substrate at the interfac e.