Electron 'sniper' targets graphene

Because of its intriguing properties graphene could be the ideal material for building new kinds of electronic devices such as sensors, screens, or even quantum computers. One of the keys to exploiting graphene's potential is being able to create atomic-scale defects - where carbon atoms in its flat, honeycomb-like structure are rearranged or 'knocked out' - as these influence its electrical, chemical, magnetic, and mechanical properties. A team led by Oxford University scientists report in Nature a new approach to a new approach to engineering graphene's atomic structure with unprecedented precision. 'Current approaches for producing defects in graphene are either like a 'shotgun' where the entire sample is sprayed with high energy ions or electrons to cause widespread defects, or a chemistry approach where many regions of the graphene are chemically reacted,' said Jamie Warner from Oxford University's Department of Materials, a member of the team. 'Both methods lack any form of control in terms of spatial precision and also the defect type, but to date are the only reported methods known for defect creation. The new method replaces the 'shotgun' with something more like a sniper rifle: a minutely-controlled beam of electrons fired from an electron microscope. 'The shotgun approach is restricted to micron scale precision, which is roughly an area of 10,000,000 square nanometres, we demonstrated a precision to within 100 square nanometres, which is about four orders of magnitude better,' explains Alex Robertson of Oxford University's Department of Materials, another member of the team.