M. G. Garnier

Influence of iron–silicon interaction on the growth of carbon nanotubes produced by chemical vapor deposition

Carbon nanotubes are often grown by chemical vapor deposition on silicon substrates covered with an iron catalyst. Photoemission and scanning electron microscopy studies presented here reveal how the iron silicide interface phase formed at elevated temperatures influences the catalytic efficiency of the iron. Moreover, we will show how the deposition of a thin layer of dense titanium nitride between the silicon substrate and the iron catalyst effectively prevents the formation of the silicide phase and consequently improves the carbon nanotubes growth.

Photoemission study of the iron-induced chemical reduction of silicon native oxide

Samples consisting of Fe deposited onto a Si wafer covered with its native oxide layer have been studied by photoelectron spectroscopy for different Fe coverages and different deposition techniques involving different kinetic energies for the deposited Fe atoms. We find that the Fe atoms are buried into the substrate even for low kinetic energy techniques, and that a reduction of the Si oxide concomitant with an oxidation of the Fe occurs. This reaction can be assisted by increasing the kinetic energy of the Fe atoms.

The Self-organization of Metal Loaded Micelles - An Approach to Prepare Ordered Arrays of Metallic Nanoislands

The preparation and characterization of hexagonally ordered pure Au nanoparticles is described. Self-assembly of diblock copolymers in solution is the driving force which leads to micellar structures. Starting, for example, with Au-salt loaded inverse micelles, monomicellar arrays exhibiting a significant hexagonal order can be prepared with taylored intermicellar distances and structure heights on top of various substrates. In order to remove the polymer matrix and to finally obtain arrays of pure Au nanoparticles, the micelles are first exposed to an oxygen plasma followed by an annealing process. Special attention is given to the chemical state of the nanoparticles applying photoelectron spectroscopy to control all preparational steps.

Grazing incidence small-angle x-ray scattering applied to the characterization of nanocomposite thin films

Grazing incidence small-angle x-ray scattering (GISAXS) allows to investigate precisely the microstructure of nanocomposite thin films containing metal nanocrystals produced using different synthesis techniques. We present results on the size, size distribution, shape, and correlation length of metallic nanoparticles embedded in different matrices fabricated by sequential pulsed laser deposition, magnetron sputtering, and ion-beam sputtering co-deposition. The morphology of the nanoparticles is discussed in terms of the different growth process that takes place in each case.