Ion-shaping of embedded gold hollow nanoshells into vertically aligned prolate morphologies

Ion beam shaping is a novel technique with which one can shape nano-structures that are embedded in a matrix, while simultaneously imposing their orientation in space. In this work, we demonstrate that the ion-shaping technique can be implemented successfully to engineer the morphology of hollow metallic spherical particles embedded within a silica matrix. The outer diameter of these particles ranges between 20 and 60 nm and their shell thickness between 3 and 14 nm. Samples have been irradiated with 74 MeV Kr ions at room temperature and for increasing fluences up to 3.8 × 1014 cm−2. In parallel, the experimental results have been theoretically simulated by using a three-dimensional code based on the thermal-spike model. These calculations show that the particles undergo a partial melting during the ion impact, and that the amount of molten phase is maximal when the impact is off-center, hitting only one hemisphere of the hollow nano-particle. We suggest a deformation scenario which differs from the one that is generally proposed for solid nano-particles. Finally, these functional materials can be seen as building blocks for the fabrication of nanodevices with really three-dimensional architectur

Development of New Kinds of Plasmonics Materials Through Swift Heavy Ion Shaping Technique

International audienceIn recent years, an innovative technique of ion-shaping of matter at the nanoscale has been proposed based on the deformation of embedded metallic nanoparticles (NPs) induced by host amorphous matrix deformation and nanoparticle melting during swift heavy ions irradiation. This technique allows the deformation of spherical metallic particles embedded in a silica matrix into several original classes of ion-shaped nanoparticles: i) facetted-like NPs, ii) nanowires iii) chromosome-like particles. The fundamental aspect of ion-matter interaction has been investigated through the modeling of the temperature profile within the nanoparticle by implementing the thermal-spike model for three-dimensional anisotropic and composite media. A straight correlation has been found between the spatial distribution of molten matter and the deformation path followed by the nanoparticles during the irradiation. Localized Surface Plasmon Resonances (LSPR) are generated along ion-shaped nanoparticles through electron excitation in a Scanning Transmission Electron Microscope. This has been investigated through nanometer-scale Electron Energy Loss Spectroscopy (EELS) analysis. The near field response of nanoparticles was investigated experimentally for different kinds of ion-shaped objects. We confirmed the near field distribution and the identification of LSPR modes of nanoparticles by modeling with a home developed Auxiliary Differential Equations-Finite Difference Time Domain (ADE-FDTD) code. This work demonstrates the possibility to use ion irradiation as a tool for the controllable fabrication of plasmonic nanostructures with topologically tunable optical properties. These ion-beam shaped composite media have potential applications spanning from plasmonic photovoltaics to Surface-Enhanced Raman Scattering (SERS) and Surface enhanced infrared absorption (SEIRA) spectroscopies

RD50 Status Report 2008 - Radiation hard semiconductor devices for very high luminosity colliders

The objective of the CERN RD50 Collaboration is the development of radiation hard semiconductor detectors for very high luminosity colliders, particularly to face the requirements of a possible upgrade scenario of the LHC.This document reports the status of research and main results obtained after the sixth year of activity of the collaboration