Large scale nanopatterning of graphene

Recently, we have shown that the shaping of atomically perfect zig-zag oriented edges can be performed by exploiting the orientation dependent oxidation in graphene, by annealing the samples in inert atmosphere, where the oxygen source is the SiO2 substrate itself. In the present study, we showed that the large scale patterning of graphene using a conventional lithography technique can be combined with the control of crystallographic orientation and edge shaping. We applied electron beam lithography (EBL) followed by low energy O+/Ar+ plasma etching for patterning mechanically exfoliated graphene flakes. As AFM imaging of the samples revealed, the controlled oxidation transformed the originally circular holes to polygonal shape with edges parallel with the zig-zag direction, showing the possibility of atomically precise, large area patterning of graphene.