Self-assembly and electron-beam-induced direct etching of suspended   graphene nanostructures
  We report on suspended single-layer graphene deposition by a transfer-printing approach based on polydimethylsiloxane stamps. The transfer printing method allows the exfoliation of graphite flakes from a bulk graphite sample and their residue-free deposition on a silicon dioxide substrate. This deposition system creates a blistered graphene surface due to strain induced by the transfer process itself. Single-layer-graphene deposition and its "blistering" on the substrate are demonstrated by a combination of Raman spectroscopy, scanning electron microscopy and atomic-force microscopy measurements. Finally, we demonstrate that blister-like suspended graphene are self-supporting single-layer structures and can be flattened by employing a spatially-resolved direct-lithography technique based on electron-beam induced etching. 
Sarah Goler, Vincenzo Piazza, Stefano Roddaro, Vittorio Pellegrini,   Fabio Beltram, and Pasqualantonio Pingue
cond-mat.mes-hall cond-mat.mtrl-sci