Controlled nanostructuring of a gold film covered with alkanethiol SAM by low energy cluster implantation
Size matters in scandium doped copper clusters
Ostwald ripening - Movie
Doped AunX+ clustersOther Nanostructures
Nanoparticles and nanostructures exhibit distinct electronic, magnetic, superconducting, optical, etc. properties because of their large surface to volume ratio and their nanometer dimensions being typically smaller than the relevant physical length scales that govern these behaviours. In order to gain insight in how these physical properties depend on size, shape and structure, we aim to fabricate and tailor nanoscale systems of different sizes, shapes, structure, etc. Of the many different techniques that can be used for producing metallic nanostructures, we focus on the following ones that are based on a self-assembly approach:
Nanoparticles created by ion-implantation
Nanoprecipitates are grown in a solid matrix by means of ion implantation. By this technique ions (e.g. Pb or Fe) are implanted in a substrate or matrix layer and are given the suitable thermal treatment so that nanoprecipitates are formed spontaneously. By carefully controlling the amount of implanted ions and the thermal treatment, the size and distance between the nanoparticles can be modified and tailored. Pb nanoparticles with sizes of a few up to 10 nm are grown in different matrices in order to study the structural properties and their influence on e.g. superconducting behavior of these nanohybrid structures. Structural properties are investigated by different techniques, including synchrotron-based small angle X-ray scattering at the DUBBLE beamline (ESRF, Grenoble) and transmission electron microscopy in collaboration with Prof. S. Bals (EMAT, U.Antwerpen)
Magnetic nanocaps on polystyrene templates
A lot of effort is focused on understanding the magnetic properties of different nanostructures. We use self-assembled periodic arrays of polystyrene spheres (few 100 nm diameter) either as a substrate or as a lift-off mask to grow magnetic nanostructures. Interestingly, the length scale of the surface modulation of this polystyrene array is of the same order as relevant magnetic lengths such as the magnetic domain size. In this way, e.g. an array of curved magnetic nanocaps can be grown with distinct magnetic properties.
Magnetism in oblique angle deposited films
Another unique self-assembly technique that we are exploring for producing magnetic nanostructures is oblique angle deposition. In this technique, porous films consisting of tilted nanorods are spontaneously formed by deposition of a molecular beam on a strongly tilted flat substrate. The principle behind this nanorod formation is based on self-shadowing effects during the growth. The nanorods are a few tens of nanometers wide. These nanorod films exhibit a very large surface to volume ratio and show peculiar magnetic anisotropy.
For this research, we are collaborating with the Nuclar Solid State Physics Group of the Institute of Nuclear and Radiation Physics at K.U.Leuven (Prof. K. Temst and Prof. A. Vantomme).
