Berlin 2005 – wissenschaftliches Programm

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O: Oberflächenphysik

O 36: Postersitzung (Elektronische Struktur, Grenzfl
äche fest-flüssig, Halbleiteroberfl
ächen und -grenzfl
ächen, Nanostrukturen, Oberfl
ächenreaktionen, Teilchen und Cluster, Struktur und Dynamik reiner Oberfl
ächen)

O 36.67: Poster

Montag, 7. März 2005, 15:00–18:00, Poster TU F

Synchrotron x-ray studies of metal and semiconductor clusters — •C. Hendrich¹, D. N. Ievlev¹, F. Meneau², W. Bras², P. Lievens¹, and K. Temst¹ — ¹Laboratory of Solid State Physics and Magnetism, K.U. Leuven, Celestijnenlaan 200 D, 3001 Leuven, Belgium — ²DUBBLE@ESRF, 6 Rue Jules Horowitz, 38043 Grenoble, France

Ensembles of nanometer sized clusters were investigated with synchrotron x-ray radiation (small angle x-ray scattering (SAXS) and wide angle x-ray scattering (WAXS)) at the DUBBLE beam line at the European Synchrotron Radiation Facility (ESRF).

The investigated samples consisted of metal and semiconductor clusters embedded in a MgO matrix. The Co, Pb and Si clusters were produced by a laser vaporization source and their size-distribution was determined by time-of-flight mass spectrometry. Embedded cluster films were grown on mica substrates by co-depositing the clusters with MgO evaporated from a Knudsen cell.

Analysis of the data from the SAXS measurements allows to estimate the cluster radii by using Guinier plots. The results are compared with the sizes obtained from time-of-flight mass spectrometry.

The WAXS data reveal information about the chemical composition of the samples, i.e. about oxidation of the clusters. The diffraction peaks from the different lattice orientations can be identified and their shifts compared to the bulk values yield information on changes in the lattice constants of the cluster material.