Oxygen induced surface segregation of Cu on the Au0.7Cu0.3(100) surface |
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| Affiliation: | 1. Material Science Innovation and Modelling (MaSIM) Research Focus Area, Faculty of Natural and Agricultural Science, North-West University (Mafikeng Campus), Private Bag X2046, Mmabatho, South Africa;2. Department of Chemistry, Faculty of Natural and Agricultural Science, North-West University (Mafikeng Campus), Private Bag X2046, Mmabatho 2735, South Africa;3. Department of Chemistry, Federal University of Petroleum Resources, P.M.B. 1221, Effurun, Nigeria;4. Non-Viral Gene and Drug Delivery Laboratory, Department of Biochemistry, University of KwaZulu-Natal, Private Bag X54001, Durban 4000, South Africa;1. University of Warsaw, Faculty of Physics, Pasteura 5 str., Warsaw 02-093, Poland;2. UTP University of Science and Technology, Institute of Mathematics and Physics, Kaliskiego 7 str., Bydgoszcz 85-796, Poland;3. University of Warsaw, Department of Chemistry, Pasteura 1 str., Warsaw 02-093, Poland |
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| Abstract: | The oxygen induced surface segregation of Cu on the Au0.7Cu0.3(100) surface was investigated by means of LEED and AES techniques. The dissociative adsorption of O2 did not take place on this clean surface for a long time exposure at least up to 104 L, and so the oxygen was forcibly introduced onto the surface through a pre-deposition of few a layers of Cu and its successive oxidation. The oxygen coverage was controlled by a heat treatment, which leads the system to a thermal equilibrium state. For the clean surface, the segregation of Au was clearly observed and the surface concentration of Au was estimated to be about 86%, greater than the bulk concentration of 70%. At low coverages below 0.16 ML, no remarkable oxygen induced segregation of Cu was observed. But, above 0.2 ML, the surface concentration of Cu was proportional to the oxygen coverage. The (2 × 4) LEED pattern was observed in a wide range of oxygen coverage. The maximum intensity of the (2 × 4) was observed at about 0.45 ML. |
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