Marie-France Beaufort

GISAXS study of cavities and {113} defects induced by neon and helium implantation in silicon

Grazing incidence small-angle X-ray scattering experiments have been performed to study the morphology of nanocavities and {113} defects formed by implantation of 5 \times 10^{16} cm^{-2} neon and helium ions in Si(001) at 50 keV. The results show that spherical cavities are formed in Si(001) implanted with Ne ions at 873 K and in Si(001) implanted with He ions at 473 K subsequently annealed at 873 K. In contrast, He-induced cavities at 873 K show {111} facets and wide size distribution due to an enhanced He mobility at high temperature. In addition to the faceted cavities, the clustering of interstitials leads to the formation of large extended planar {113} defects whose size has been estimated to be about 100 nm.

Surface Plasmon Resonance Effect on the Optical Properties of TiO2 Doped by Noble Metals Nanoparticles

Nanocomposite thin films composed of a TiO2 matrix doped with noble metals nanoparticles (MNPS), Au and Ag, were deposited on Si (100) and glass substrates by dc magnetron sputtering. The samples were annealed in a protective atmosphere at temperatures ranging from 200 to 700 °C. The main goal of this work is to characterize and compare the Surface Plasmon Resonance (SPR) behaviour in both systems. The studies have been focused on the growth of the nanoclusters and on their role on the optical properties of the films. Size, shape and distribution of the nanoclusters embedded on the titanium oxide dielectric matrix are reported as key factors on the SPR behaviour in both systems (Au:TiO2 and Ag:TiO2). The MNPs grew due to diffusion mechanisms, which were led by the annealing treatments, even at the highest annealing temperatures. Evidences of the correlation between the nanocomposite film structural changes and the evolution of the optical properties due to the SPR activity are reported. The SPR phenomenon manifests itself as a wide band on the visible range on the absorption spectra, and it is confirmed by an important change on the surface colour tones of the samples.

Comparison of Defects Created by Plasma-Based Ion Implantation and Conventional Implantation of Hydrogen in Germanium

(001) n-type Ge has been implanted at given fluence and intermediate temperature with hydrogen ions using two processes: conventional in-line implantation and plasma based ion implantation. The as-created microstructure has been compared using transmission electron microscopy. In particular, it has been shown that the major differences observed are due to the implantation temperature, much higher during the PBII process. This suggests that plasma based ion implantation could be used for layer transfer in spite of a higher surface roughness observed after the PBII process.