Abstract
Surface sensitive X-ray absorption spectroscopy has been used for investigating the differences in the environment of copper atoms at the Cu/Al 2O 3 interface for different oxidation states of the α-alumina substrate. We have prepared in situ both oxidised and reduced α-alumina surfaces and have evaporated equal amounts of copper (∼ 80% monolayer) on each. Under our experimental conditions, we infer that: (a) the interface grows via the Volmer-Weber mode rather than the Stranski-Krastanov mode suggested in the literature. (b) The morphology of supported Cu clusters depends strongly on the oxidation state of the alumina. For equal amounts of copper, much larger clusters are found on reduced Al 2O 3(0001) substrates than on oxidised substrates.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have