Selective etching of armchair edges in graphite

We present an easy and fast procedure for producing graphene and few layer graphite nanostructures with edges of predefined crystallographic orientation. By annealing graphite in an oxygen containing atmosphere, of controlled composition hexagonal surface structures can be etched in a controlled way. We show that the process can be made crystallographically selective and the resulting edges are of armchair type. The dimensions of the resulting nanostructures can be well controlled by the oxidation rate, through accurately adjusting the etching parameters, such as oxygen concentration, annealing temperature and duration. The oxidation preferentially starts at defect sites either naturally present in the sample or produced on purpose, the latter holding the promise of a more accurate control over the resulting structures.