Controlled nanocutting of graphene

Abstract

Rapid progress in graphene-based applications is calling for new processing techniques for creating graphene components with different shapes, sizes, and edge structures. Here we report a controlled cutting process for graphene sheets, using nickel nanoparticles as a knife that cuts with nanoscale precision. The cutting proceeds via catalytic hydrogenation of the graphene lattice, and can generate graphene pieces with specifi c zigzag or armchair edges. The size of the nanoparticle dictates the edge structure that is produced during the cutting. The cutting occurs along straight lines and along symmetry lines, defined by angles of 60º or 120º, and is defl ected at free edges or defects, allowing practical control of graphene nano-engineering.

Catalytic subsurface etching of nanoscale channels in graphite

“…Subsequently deposited Ni nanoparticles resting at these artificial and at the natural step edges serve as catalyst for hydrogenation of carbon when the sample is exposed to high temperature in H atmosphere (see Methods for more details). It is understood that the nanoparticle is dragged into the void where carbon atoms have been removed at the edge of the sheet, catalyses further hydrogenation of carbon and successively etches a channel from the edge into the sheet, following the main symmetry directions of carbon lattice 1,3,[5][6][7][8][9][10] (see also Fig. 1a).…”

“…Careful inspection of images in previous publications indicates that tunnel formation may occur also in other systems etched by Ni, Ag and Co [4][5][6]8,10 , although it has never been explicitly reported before.…”

“…In recent years it has attracted renewed attention as a possible route for nanopatterning of graphene, especially for the production of graphene nanoribbons. Metallic nanoparticles etch the surface layers of graphite [1][2][3][4][5][6][7][8] , as well as single-layer graphene sheets [9][10] . The process is anisotropic along the crystallographic highsymmetry directions, that is, the zigzag /11-20S or armchair /10-10S directions.…”

“…The process is anisotropic along the crystallographic highsymmetry directions, that is, the zigzag /11-20S or armchair /10-10S directions. Nanoparticles consisting of various metals, such as Ni 2,8,9,10 , Fe 2,7 , Pt 3 , Co 2,4,5 and Ag 6 , are known to etch channels on graphite surfaces. It was shown that the etching direction could be influenced by an external magnetic field when Co particles were used 11 .…”

“…To date, clear evidence has been reported only for open channels on the surface of graphite, whereas subsurface etching remains unclear 4,5,8 . In this study, we demonstrate the subsurface etching of highly oriented pyrolytic graphite (HOPG) by Ni nanoparticles.…”