Synthesis, Morphology And Properties Of Polycrystalline Graphene Membranes
Graphene has recently emerged as a promising material for a wide range of potential applications, thanks to its outstanding electrical, mechanical, thermal and optical properties. This interest has fueled many efforts to establish methods for large scale graphene synthesis. One of the most promising scalable approaches is to obtain graphene on metal surfaces, most notably on copper, via chemical vapor deposition (CVD). We have developed novel fabrication methods to obtain CVD graphene devices in large quantities. This allowed a thorough study of the polycrystalline structure in CVD graphene, as well as the characterization of mechanical and electrical properties, which are affected by graphene's grain structure. We found that grain boundaries are not the dominant factor in determining the electrical properties of devices. However, grain boundaries were observed to strongly affect graphene mechanical properties. For example, tearing and unzipping along grain boundaries were observed in graphene membranes, as a result of nanoindentation. Finally, we have fabricated microcapsules featuring atomically thin windows made of reinforced double-layer CVD graphene. We have demonstrated the use of these windows for scanning electron microscopy (SEM) of samples in water. As proof of principle, we have imaged metallic nanoparticles in solution, with resolution and signal to noise ratio superior to those obtained with polyimide-based commercially available environmental cells.
carbon; nanostructures; graphene
Ralph, Daniel C; Hennig, Richard G.
Ph. D., Applied Physics
Doctor of Philosophy
dissertation or thesis