A perspective on nanoscale pattern formation at surfaces by ion-beam irradiation

Abstract

The formation of periodic patterns on the surfaces of many solid materials undergoing ion-beam irradiation has long been known.The advent of high resolution characterization techniques elucidated the nanoscopic traits of this self-organization process, enablinga wide range of applications for the nanostructures thus produced, from optoelectronic to biomedical. Meanwhile, full theoreticalunderstanding of the technique has been challenged by its multiscale nature, whereby the external perturbation implemented by theion beam acts at a much slower rate (typically, one ion arrives per square-nm every second) than the microscopic processes, like collision cascades and material transport, which try to relax such external perturbations (collision cascades or surface diffusion attemptsusually relax after a few picoseconds). Here, we present a Perspective on the main developments that have led to the current understanding of nanoscale pattern formation at surfaces by ion-beam irradiation, from the points of view of experiments, applications,and theory, and offer an outlook on future steps that may eventually facilitate full harnessing of such a versatile avenue to materialsnanostructuring.