# Perforating freestanding molybdenum disulfide monolayers with highly charged ions

## TL;DR

This study demonstrates that irradiation with highly charged ions can efficiently create well-defined, narrow-sized pores in freestanding molybdenum disulfide monolayers, with potential applications in filtration and sensing.

## Contribution

It introduces a novel ion irradiation technique using highly charged ions to fabricate precise pores in MoS₂ monolayers, highlighting the role of electronic excitation in defect formation.

## Key findings

- Pore creation efficiency increases linearly with ion potential energy.
- Pore sizes depend on the potential energy of the ions used.
- Irradiation produces pores with radii between 0.3 and 3 nm.

## Abstract

Porous single layer molybdenum disulfide (MoS$_2$) is a promising material for applications such as DNA sequencing and water desalination. In this work, we introduce irradiation with highly charged ions (HCIs) as a new technique to fabricate well-defined pores in MoS$_2$. Surprisingly, we find a linear increase of the pore creation efficiency over a broad range of potential energies. Comparison to atomistic simulations reveals the critical role of energy deposition from the ion to the material through electronic excitation in the defect creation process, and suggests an enrichment in molybdenum in the vicinity of the pore edges at least for ions with low potential energies. Analysis of the irradiated samples with atomic resolution scanning transmission electron microscopy reveals a clear dependence of the pore size on the potential energy of the projectiles, establishing irradiation with highly charged ions as an effective method to create pores with narrow size distributions and radii between ca. 0.3 and 3 nm.