Model for Nanopore Formation in Two-Dimensional Materials by Impact of Highly Charged Ions

Abstract

We present a first qualitative description of the atomic dynamics in two-dimensional (2D) materials induced by the impact of slow, highly charged ions. We employ a classical molecular dynamics simulation for the motion of the target atoms combined with a Monte Carlo model for the diffusive charge transport within the layer. Depending on the velocity of charge transfer (hopping time or hole mobility) and the number of extracted electrons which, in turn, depends on the charge state of the impinging ions, we find regions of stability of the 2D structure as well as parameter combinations for which nanopore formation due to Coulomb repulsion is predicted.

Charge exchange of slow highly charged ions from an electron beam ion trap with surfaces and 2D materials

“…A related approach was taken by Grossek et al [132], who also introduce an excitation in a 2D material to mimic an HCIimpact: Here, a honeycomb lattice with graphene lattice constant is used, but other materials can be addressed using adjusted hopping times. A relaxation of the material is analysed, where atoms with kinetic energies above their binding energy are assumed to be emitted from the material.…”

Role of Chemical Etching in the Nucleation of Nanopores in 2D MoS2: Insights from First-Principles Calculations

“…In this regard, although chemical vapor deposition (CVD) of MoS 2 has been modeled extensively, − fewer studies have focused on understanding the formation of extended defects in the material. , One of the first studies reporting intrinsic defects in monolayer MoS 2 was by Zhou and co-workers, where the authors used microscopy and ab initio calculations to investigate various defects, edges, grain boundaries, and dislocations present in CVD-grown MoS 2 , providing an avenue for controlling nanopore synthesis . Chemical synthesis routes for nanopore formation include annealing with oxygen, , steam etching, and plasma etching .…”

A contactless single-step process for simultaneous nanoscale patterning and cleaning of large-area graphene

“…Using ultraviolet (UV) oxidative etching, large-area nanoporous graphene can be produced with a large number of sub-nanometer pores, suitable for water desalination and filtering applications [10,26]. Irradiation with highly charged low energy ions and swift heavy ions have also been demonstrated for perforating self-supporting graphene and molybdenum disulfide monolayers (MLs) [27][28][29][30][31]. However, for structuring graphene membranes with pre-defined patterns by oxidative or ion beam techniques pattern-defining layers are necessary.…”