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Ballistic Transport in Graphene Suggests New Type of Electronic Device


Walt de Heer, a Regents professor in the School of Physics at the Georgia Institute of Technology, poses with equipment used to measure the properties of graphene nanoribbons.

Researchers reported ballistic transport properties in graphene nanoribbons that are just 40 nanometers wide.

Credit: Rob Felt/Georgia Tech

Walt de Heer, a Regent’s professor in the School of Physics at the Georgia Institute of Technology, poses with equipment used to measure the properties of graphene nanoribbons. De Heer and collaborators from three other institutions have reported ballistic transport properties in graphene nanoribbons that are about 40 nanometers wide.

The discovery indicates the nanoribbons act more like optical waveguides or quantum dots, which allows electrons to flow smoothly along the edges of the material and could lead to new types of electronic devices based on graphene's ability to carry electrons with virtually no resistance. The ballistic transport properties exceed theoretical conductance predictions for graphene 10-fold, according to the researchers.

"This could result in a new class of coherent electronic devices based on room temperature ballistic transport in graphene," says Georgia Tech professor Walt de Heer.

The researchers found that touching the nanoribbons with a single probe doubles the resistance, and touching it with two probes triples the resistance. "We have done systematic studies to show that when you touch the nanoribbons with a probe, you introduce a method for the electrons to scatter, and that changes the resistance," de Heer says.

The advantage of fabricating graphene nanoribbons this way is that it produces edges that are perfectly smooth, which allow electrons to flow through the nanoribbons without disruption. "There is a lot of fundamental physics that needs to be done to understand what we are seeing," de Heer says.

From Georgia Tech News Center
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