Nanometer size hole fabrication in 2d ultrathin films with cluster ion beams

Abstract

Gas cluster ion beams are proposed as a new tool for producing nanometer sized holes in ultrathin 2D films. Surfaces of films of graphene, graphene oxide, MoS2, and HOPG, and also silicon as a reference, were irradiated by Ar gas cluster ion beams (Exogenesis Corporation, Billerica, MA USA). The results were analyzed using atomic force microscopy (AFM) and Raman spectroscopy. Ar gas cluster ion acceleration energy was 30 keV and total ion fluences ranged from 1×108 to 1×1013 cm-2. Uniformly distributed holes, typically in the range of 10 to 25 nanometers in diameter, produced by the cluster ions, were observed on the surface of graphene oxide. To the best of our knowledge, this is first experimental observation of such holes.

Neutralization Dynamics of Slow Highly Charged Ions in 2D Materials

“…Whether electrons emitted by ICD (from target atoms) and those from partly deexcited ions (at a later stage) can be distinguished by their energy (or angular distribution) needs to be clarified in future experiments. Electronic excitations in the surface produced by ICD of hollow atoms can later drive nanostructure formation at insulating surfaces (see Figure 3a-c) and perforation of 2D insulators (see Figure 5) due to electron-phonon coupling or Coulomb explosion [64]. At metallic surfaces or metallic 2D materials, electronic excitations are highly mobile and dissipate the excitation energy on a time scale much faster than atomic motion at surfaces.…”