Energy dependent sputtering of nano-clusters from a nanodisperse target and embedding of nanoparticles into a substrate

TL;DR

This study investigates how ion energy affects sputtering and embedding of gold nanoparticles on silicon, revealing that different energy regimes lead to varying sputtering yields and embedding depths, with implications for nanostructure modification.

Contribution

It provides a detailed analysis of energy-dependent sputtering and embedding behaviors of gold nanoparticles under ion irradiation, highlighting the effects of ion energy and incidence angle.

Findings

Maximum sputtering occurs at high electronic energy loss (100 MeV)

Embedding is reduced at high ion energies but enhanced at oblique angles

Embedded gold-silicide forms after ion irradiation

Abstract

Au nanoparticles, prepared by thermal evaporation under high vacuum condition on Si substrate, are irradiated with Au ions at different ion energies. During ion irradiation, embedding of nanoparticles as well as ejection of nano-clusters is observed. Ejected particles (usually smaller than those on the Si substrate) due to sputtering are collected on carbon-coated transmission electron microscopy (TEM) grids. Both the TEM grids and the ion-irradiated samples are analyzed with TEM. Unirradiated as well as irradiated samples are also analyzed by Rutherford backscattering spectrometry (RBS). In the case of low energy (32 keV) ions, where the nuclear energy loss is dominant, both sputtering and embedding are less compared to medium energy (1.5 MeV). In the high energy regime (100 MeV), where the electronic energy loss is dominant, sputtering is maximum but practically there is no embedding. Ion bombardment of surfaces at an angle with respect to the surface-normal produces enhanced embedding compared to normal-incidence bombardment. The depth of embedding increases with larger angle of incidence. Au nanoparticles after ion irradiation form embedded gold-silicide. Size distribution of the sputtered Au clusters on the TEM grids for different ion energy regimes are presented.