Fabrication of nanopores in a graphene sheet with heavy ions: a molecular dynamics study

TL;DR

This study uses molecular dynamics simulations to explore how heavy ion irradiation can create controlled nanopores and nanostructures in graphene, revealing effects of ion parameters on damage and pore formation.

Contribution

It demonstrates the feasibility of fabricating controlled nanopores in graphene through heavy ion irradiation, highlighting the influence of ion parameters on damage mechanisms.

Findings

Net-like defective structures form at low ion fluence.

Perfect nanopores with smooth edges appear at high ion fluence.

Ion damage efficiency depends differently on parameters than semi-empirical models.

Abstract

Molecular dynamics (MD) simulations were performed to study the formation process of nanopores in a suspended graphene sheet irradiated by using energetic ions though a mask. By controlling the ion parameters including mass, energy and incident angle, different kinds of topography were observed in the graphene sheet. Net-like defective strucutures with carbon atom chains can be formed at low ion fluence, which provides the possibility to functionalize the irradiated sample with subsequent chemical methods; finally a perfect nanopore with smooth edge appears as the ion fluence is high enough. We found that the dependence of ion damage efficiency on ion fluence, energy and incident angle are different from that predicted by the semi-empirical model based on the binary-collision approximation, which results from the special structure of graphene. Our results demonstrate that it is feasible to fabricate controlled nanopores/nanostructures in graphene via heavy ion irradiation.