A method for joining individual graphene sheets

A graphene-based device requires the graphene to have an ideal shape, structure, and orientation, and be large enough, to allow them to be formed into a new device. Here the joining of individual single-layer and multi-layer graphene is performed in a transmission electron microscope-scanning tunneling microscope (TEM-STM) holder inside a 200 kV field emission TEM. Attempts have been made to join individual graphene sheets (GSs) with the so-called top-to-top and layer-to-layer geometries by applying a voltage. In the two geometries, the top-to-top form has resulted in a seamless joining for both single-layer and multi-layer GSs. The as-joined GSs show the same excellent electrical and mechanical properties as those of the original GSs. Large Joule heating originating from the field emission current will cause atom diffusion and self-assembly and then rearrangement of carbon networks at the GS edge front. In this way individual GSs could be extended and mended with the so-called top-to-top geometries by applying a constant voltage, to meet the required and desired shape, size, configuration, and functions for a variety of the special micro/nano scaled devices. (C) 2012 Elsevier Ltd. All rights reserved.