Graphene sheet. Graphene is a planar sheet of carbon atoms arranged in a hexagonal pattern. Stacked graphene sheets form the common material graphite, used in pencils and industry. Graphene is very strong and flexible. It transports electrons highly efficiently and may one day replace silicon in computer chips and other technology applications. The 2010 Nobel Prize for Physics was awarded to Andre Geim and Konstantin Novoselov for their work on graphene sheets.