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Dépôt d'agrégats préformés sur surface de graphite. Etude de l'interaction métal-oxyde à l'échelle nanométrique.

Abstract : This study deals with stability of nanostructures formed by silver clusters deposition on graphite with respect to annealing or inclusion of oxides as well as the possibility of spontaneously organizing them via the surface defects.
The chemically heterogeneous clusters are produced by reactive nucleation and are identified by high resolution mass spectrometry. Deposits are imaged by electron microscopy and are defined by a parameter to characterize morphologies.
The presence of oxygen in the clusters causes the fractal form to decompose into a series of equally sized and equidistant fragments. The analogy with Rayleigh instabilities is discussed. This resulting pattern differs from that obtained by thermal activation although also driven by surface self-diffusion.
When molybdenum oxide is added to oxygen for nucleation, synthesis of free silver molybdate clusters is achieved by laser annealing. This transition in mass spectra results on the substrate in a reduction of several orders of magnitude of cluster diffusion and in a morphological transition: the grown islands, called nanochains, present an anisotropic growth and a periodic structure. They are very stable in shape with respect to annealing. A growth mechanism is proposed.
Film “morphodrome” according to the cluster chemical composition is established and the possibility of controlling the film properties is shown. This effect is added to that of particular graphite defects for which a correlation between defect dimension and cluster diffusion is highlighted for the growth and the organization of the islands.
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Contributor : Aurélie Lando <>
Submitted on : Tuesday, April 4, 2006 - 3:53:31 PM
Last modification on : Monday, February 15, 2021 - 10:38:50 AM
Long-term archiving on: : Saturday, April 3, 2010 - 11:06:49 PM


  • HAL Id : tel-00012080, version 1



Aurélie Lando. Dépôt d'agrégats préformés sur surface de graphite. Etude de l'interaction métal-oxyde à l'échelle nanométrique.. Physique [physics]. Université Paris Sud - Paris XI, 2005. Français. ⟨tel-00012080⟩



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