Creation of multiple nanodots by single ions

TL;DR

This paper demonstrates that high-energy ions can create multiple nanodots on surfaces by adjusting the angle of incidence, enabling controlled nanostructure formation through localized electronic excitations.

Contribution

It introduces a method to produce multiple nanodots with a single ion by using grazing incidence angles, allowing for controlled nanostructure patterning.

Findings

Multiple nanodots can be created by a single ion at grazing angles.

The number of nanodots can be controlled by varying the incidence angle.

Nanoscale hillocks are formed due to localized electronic excitations.

Abstract

In the challenging search for tools that are able to modify surfaces on the nanometer scale, heavy ions with energies of several 10 MeV are becoming more and more attractive. In contrast to slow ions where nuclear stopping is important and the energy is dissipated into a large volume in the crystal, in the high energy regime the stopping is due to electronic excitations only. Because of the extremely local (< 1 nm) energy deposition with densities of up to 10E19 W/cm^2, nanoscaled hillocks can be created under normal incidence. Usually, each nanodot is due to the impact of a single ion and the dots are randomly distributed. We demonstrate that multiple periodically spaced dots separated by a few 10 nanometers can be created by a single ion if the sample is irradiated under grazing angles of incidence. By varying this angle the number of dots can be controlled.