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A MODEL SYSTEM TO GIVE AN INSIGHT INTO THE BEHAVIOUR OF GOLD NANOPARTICLES UNDER ION IRRADIATION

Abstract : Nanocomposites fabricated with ion-based techniques have a number of attractive characteristics. However, the main and most crucial diculty in obtaining commercial NPs-based devices is the inability to produce a suitable narrow size and spatial NP distributions. The objective of this thesis is twofold: i) to go further in the description of the behavior of the ion-driven NPs and ii) to overcome the limitations related to the ion-beam techniques providing a guideline methodology to rationalize the synthesis of NPs when ion-beams are used. Thus, a model system is fabricated. It consists of chemically synthesized metallic nanoparticles sandwiched between two silica layers. We show how the ion irradiation and the temperature can be used to tune the size distribution of the embedded NPs. Moreover, we show that when an initially large NPs size distribution is considered, the study of the growth kinetic of the NPs under irradiation can be problematic. Our model system is than used to investigate in detail the behavior of the NPs under irradiation. We show that the evolution of the precipitate phase under irradiation is successfully described by an Ostwald ripening mechanism in an open system limited by the diusion. Moreover, the concentration threshold for nucleation as well as the surface tension and the gold diusivity in silica under irradiation is estimated. Finally, direct and inverse Ostwald ripening processes under irradiation are systematically investigated and the existing theoretical models experimentally checked.
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Contributor : Yaasiin Ramjauny <>
Submitted on : Friday, February 11, 2011 - 10:19:50 AM
Last modification on : Friday, July 31, 2020 - 9:24:06 AM
Long-term archiving on: : Tuesday, November 6, 2012 - 1:50:24 PM

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  • HAL Id : pastel-00565145, version 1

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Yaasiin Ramjauny. A MODEL SYSTEM TO GIVE AN INSIGHT INTO THE BEHAVIOUR OF GOLD NANOPARTICLES UNDER ION IRRADIATION. Materials Science [cond-mat.mtrl-sci]. Ecole Polytechnique X, 2010. English. ⟨pastel-00565145⟩

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