Monday, February 20, 2012

Breakthrough in Graphene Could Lead to Thinner, More Powerful Electronics

A breakthrough in controlling graphene could see the highly conductive and super-strong ‘wonder material’ replace silicon and change the face of electronics, leading to faster, thinner gadgets.

Researchers at Northwestern University in Chicago have made a giant step in overcoming one of the hurdles blocking the development of graphene for use in everyday devices – that it’s difficult to electrically ‘turn off’ the flow of current through it.

Now scientists have found a way of chemically altering the material to ‘tune’ its electronic properties and make it more functional.Until now the most prevalent strategy is the ‘Hummers method’, a process developed in the 1940s that oxidises graphene, but that method relies upon harsh acids that irreversibly damage the fabric of the graphene lattice.

Researchers at Northwestern's McCormick School of Engineering and Applied Science have recently developed a new method to oxidise graphene without the collateral damage encountered in the Hummers method.

Their oxidation process is also reversible, which enables further tunability over the resulting properties of their chemically modified graphene.

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To create the graphene oxide, researchers leaked oxygen gas (O2) into an ultra-high vacuum chamber. Inside, a hot tungsten filament was heated to 1500C, causing the oxygen molecules to dissociate into atomic oxygen. The highly reactive oxygen atoms then uniformly inserted into the graphene lattice.

The resulting material possesses a high degree of chemical homogeneity. Spectroscopic measurements show that the electronic properties of the graphene vary as a function of oxygen coverage, suggesting that this approach can tune the properties of graphene-based devices.

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