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Journal of Nanomaterials
Volume 2008, Article ID 475168, 5 pages
http://dx.doi.org/10.1155/2008/475168
Research Article

Metallic Nanoparticles Embedded in a Dielectric Matrix: Growth Mechanisms and Percolation

1Departament de Física Fonamental i Institut de Nanociència i Nanotecnologia, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain
2Departament de Física Aplicada i Òptica i Institut de Nanociència i Nanotecnologia, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain

Received 1 October 2007; Accepted 26 December 2007

Academic Editor: Ping Xiao

Copyright © 2008 M. García del Muro et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

We present a study of the preparation and structural characterization of granular Ag-ZrO2, Co-ZrO2, and Au-ZrO2 thin films grown by pulsed laser deposition (PLD) in a wide range of volume fraction x of metal (0.08<xAg<0.28, 0.06<xCo<0.40, and 0.08<xAu<0.55). High-resolution transmission electron microscopy (HRTEM) showed regular distribution of spherical Au, Co, and Au nanoparticles having very sharp interfaces with the amorphous matrix. The structural results are compared aiming to stress the effect of the actual microstructure on the percolation threshold. Two different mechanisms of particle growing as a function of the metal content are evidenced: nucleation and particle coalescence, with their relative significance depending strongly on the type of metal, giving rise to very different values of the percolation threshold (xc(Ag)0.28, xc(Co)0.35, and xc(Au)0.55).