Matrix-material dependence on the elongation of embedded gold nanoparticles induced by 4 MeV C₆₀ and 200 MeV Xe ion irradiation

Abstract

We report the elongation of embedded Au nanoparticles (NPs) in three different matrices, i.e. amorphous carbon (a-C), crystalline indium tin oxide (InxSn1-xOz; ITO) and crystalline calcium fluoride (CaF2), under irradiations of 4 MeV C60+ cluster ions and 200 MeV Xe14+ ions. Under 4 MeV C60 cluster irradiation, strong sputtering is induced in CaF2 layer so that the whole the layer was completely lost at a fluence of 5 × 1013 ions cm−2. Au NPs were partly observed in the SiO2, probably due to the recoil implantation. Amorphous carbon (a-C) layer exhibits low sputtering loss even under 4 MeV C60 irradiation. However, the elongation in a-C layer was low. While the ITO layer showed a certain decrease in thickness under 4 MeV C60 irradiation, large elongation of Au NPs was observed under both 4 MeV C60 and 200 MeV Xe irradiation. The ITO layer preserved the crystallinity even after large elongation was induced. This is the first report of the elongation of metal NPs in a crystalline matrix.

Insights into nanoparticle shape transformation by energetic ions using atomistic simulations

“…These results may be used as a starting point to understand seemingly incompatible experimental observations: elongation induced by individual impacts to NPs 4,31 but the overall process influenced by the embedding matrix 2,9,12 . The results show unambiguously that nearby impacts affect the stress within the NP, which changes the elongation rate.…”

“…Recently, the first experimental investigations studying the dependence of the effect on the embedding matrix were reported 10,12 . We believe that our results will be important to interpret the experiments, as they show that the metal-matrix interactions affect the elongation rate.…”

“…Moreover, theoretical continuum mechanical considerations do not support the idea of deformation by hammering 23 . Recent works include the observation of elongation using C 60 ions 11 , studies on embedded NPs at the interface of silica and silicon nitride 10 , and the observation of elongation in NPs embedded in crystalline indium tin oxide 12 . See for example, Refs.…”

“…SHI irradiation causes a peculiar shape transformation induced to nanoparticles (NPs) embedded in amorphous SiO 2 matrices. Numerous experiments [1][2][3][4][5][6][7][8][9][10][11][12] have shown that spherical NPs can become elongated in the ion beam direction and evolve into prolate shapes or rods. While intriguing from an application point of view, the shaping process also offers unique insights into the fundamentals of ion-solid interactions.…”

Anisotropic deformation of colloidal particles under 4 MeV Cu ions irradiation

“…It has been demonstrated that different morphologies can be obtained based on the size of the initial sample by researchers at CNRS in Caen, France [35]. Precision aligned nanorods can be easily fabricated using swift heavy ion beam irradiation [36][37][38][39][40][41][42][43][44]. An investigation by the author and coworkers [45] examined the relationship between metal particle size and deposited energy.…”