Oxide- and oxide-supported nanoclusters on quasicrystals

As a result of high-temperature oxidation, well-ordered and few-nanometer-large Al-oxide domains grow on icosahedral AlPdMn and decagonal AlCoNi quasicrystals. The Al-oxide domains possess an oxygen sublattice in hexagonal structure, which is locally commensurate and in registry with the quasicrystal. The diffraction patterns disclose the presence and the interaction of the domain boundaries but also deliver, under certain conditions, fractional-order spots, characteristic of a $2sqrt3,(1times 1)Rpm30^circ$ reconstruction. The small lateral extension of the domains can be used for the growth of metal particles in the same size-region. The structural characterization of the oxide and oxide-supported overlayers has been investigated using low-energy electron diffraction and secondary-electron imaging. Information about the chemical composition in a near-surface region and the oxide growth kinetics has been obtained by means of Auger electron spectroscopy.