Size- and shape-dependence of the graphene to graphane transformation in the absence of hydrogen

Graphene is a fascinating material with many unique properties, some of which have lead to the development of basic circuit elements with atomic level precision. However, large area, pristine graphene is a semi-metal and is therefore unsuitable for any electronic applications needing a finite band gap. By contrast, recently discovered graphane has been shown to be an insulator and the use of a combination of graphene and graphane has been suggested to be one method to overcome this problem. We show here that as graphene is charged localized regions of graphene are transformed from sp(2) bonded into sp(3) bonded, giving rise to hydrogen-less graphane which, if experimentally realised, may lead to a way of combining graphene and graphane in the same material.