Graphene has two distinct types of edges produced when it is cut – armchair type or zigzag type – which correspond to the two crystal axis of graphene. These edge types are predicted theoretically to have distinct electronic, magnetic, and chemical properties, but current fabrication methods have no way of controlling which type of edge is produced and are dominated by disorder.
A solution to this problem has now been found. Nanotechnology researchers have demonstrated anisotropic etching in single-layer graphene which produces connected graphene nanostructures with crystallographically oriented edges. This opens many future avenues to study graphene nanostructures such as nanoribbons, nanoconstrictions, and quantum dots with crystallographic edges.
The researcers discovered that in single layer graphene this nickel nanoparticle etching had an even more pronounced behavior than in graphite. The team found that with their technique – anisotropic etching of single-layer graphene by thermally activated nickel nanoparticles – the cuts were running along a single crystallographic axis (in graphite cuts are produced in both of graphene's two crystallographic directions) and that they were uniformly small in size.