Ion Beam Shaping of Au Nanoparticles

To study the ion-shaping effects on metal NPs in greater detail we conducted experiments on the ion irradiation of spherical Au NPs. We studied the influence of NP size, areal density and/or concentration and ion kinetic energy on the shaping characteristics of Au NPs that are embedded, not only within a silica matrix, but also within silicon nitride films and silicon oxide/silicon nitride layer structures, and layer structures involving amorphous silicon. In these studies, the nanoparticles were embedded in the layered structure, in a single plane parallel to the surface. Taking advantage of the monodispersity and commercial availability of Au nanoparticles we were able to study the ion-shaping process over a large range of NP size from 8 to 100 nm diameter under irradiation with ion energy in the range from 10 MeV to 5 GeV, corresponding to the energy loss, ranging from ~4 to 17 keV/nm in SiO2. Depending on their pristine size, we show that the shaping is not only limited to the transformation of spherical NPs into prolate nanorods or nanowires. Because the comprehension of the ion-shaping phenomenon is far from complete, we strongly believe that the data described in this thesis are useful for getting a better understanding of the ion shaping phenomenon and for advancement of a possible application of this process.