Transformation of graphene into graphane in the absence of hydrogen

Density functional based tight binding simulations were used to explore the fundamental charging of graphene nanoflakes, either by an electron-beam or electric current, to determine the effective failure limit with respect to induced charge. During this study we find that the failure limit of graphene is sufficiently high as to pose no problem to the operation of graphene-based electronic devices, but that localized regions may be transformed from an sp(2)-bonded into an sp(3)-bonded material before the failure limit. These regions are consistent with the carbon framework observed in graphane, but occur in the absence of hydrogen. (C) 2009 Elsevier Ltd. All rights reserved.