When 4:00 PM - 5:00 PM Sep 23, 2011
Where Stamps Auditorium, Walgreen Center
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Ju Li, Nuclear Engineering, MIT


Plumber’s Wonderland Found on Graphene

Curvy nanostructures such as carbon nanotubes and fullerenes have extraordinary properties but are difficult to pick up and assemble into devices after synthesis. We have performed experimental and modeling research into how to integrate curvy nanostructures on flat graphene, taking advantage of the fact that graphene bends easily after open edges have been cut on it, which can then fuse with other open edges, like a plumber connecting metal fittings. By applying electrical current heating to few-layer graphene inside an electron microscope, one effectively anneals out the radiation damage and observes the in situ creation of many interconnected, curved carbon nanostructures, such as graphene bilayer edges (BLEs) aka “halfnanotubes”, BLE polygons and nanotube-BLE junctions connecting multiple layers of graphene. A novel piezoelectric effect causes the BLEs to have large permanent electric dipoles of 0.87 and 1.14 Debye/Å for zigzag and armchair inclinations, respectively. Unlike carbon nanotubes, which fold graphene by 2 probation and are highly poly-disperse in chiralities and radius, BLEs are highly mono-disperse structures due to the protation and a lattice orientation constraint during processing. Further investigations indicate that multiple-layer graphene offers unique opportunities for tailoring carbon-based structures and engineering novel nano-devices with complex topologies.

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