"Anisotropic Etching and Crystallographic Nanoribbon Formation in
Single-Layer Graphene"

Abstract:

We demonstrate anisotropic etching of single-layer graphene by
thermally-activated nickel nanoparticles. Using this technique, we
obtain sub-10nm nanoribbons and other graphene nanostructures with
edges aligned along a single crystallographic direction. We observe a
new catalytic channeling behavior, whereby etched cuts do not
intersect, resulting in continuously connected geometries.  Raman
spectroscopy and electronic measurements show that the quality of the
graphene is resilient under the etching conditions, indicating that
this method may serve as a powerful technique to produce graphene
nanocircuits with well-defined crystallographic edges.