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.