Researchers from China have shown that by irradiating ultrathin nanofibres of poly(methyl methacrylate) (PMMA) with a beam of electrons from a conventional transmission electron microscope, they can convert the fibers into nanoribbons of graphene.1 The discovery could provide a simply means of developing high- graphene based electronic devices.

Graphene is a single layer of carbon atoms arranged in a hexagonal lattice. Despite being just one atom thick it is both chemically and mechanically stable. But even more remarkable are its electronic properties.

The electrical charge within graphene travels at speeds just 300 times less than the speed of light. Moreover, they can travel thousands of times further in graphene without scattering than in conventional silicon. Such characteristics should, in principle, enable the realization of ultrafast electronic devices and circuits from graphene.

Yet, these same properties preclude the development practical electronic devices because it is not enough to be able to make charge flow efficiently, but it is also necessary to stop that flow just as efficiently. And, in graphene, it is difficult to stop the flow of electrical current, which is a major hurdle limiting the fabrication of even the simplest electronic devices.

Interestingly, current in narrow ribbons of graphene—rather than sheets—can be switched off much more effectively. However, synthesizing these nanoribbons has until now been a slow and tedious process. But the discovery by Erqing Xie from Lanzhou University and colleagues, could make fabrication of graphene ribbons much easier.

Fig. 1: Electron microscope image of graphene nanoribbons that result when electrospun PMMA nanofibres are exposed for long enough to an electron beam.

While studying electrospun PMMA nanoribbons in an electron microscope the researchers noticed an unexpected transformation. With increasing exposure to the microscope's beam, the fibers gradually became thinner and narrower. Further analysis showed that they had in fact transformed into ribbons of multilayered graphene (Fig. 1) in some sections just three monolayers thick. With further development, the ability to create and control graphene nanoribbons from a network of plastic fiber may be a promising new route to the creation of complex graphene electronic circuits.