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The problem of electrons moving freely through graphene with no control has finally been solved.

Researchers from Rutgers University-New Brunswick have tamed the unruly electrons in graphene by sending voltage through a high-tech microscope with an extremely sharp tip about the size of an atom.

“This shows we can electrically control the electrons in graphene,” Eva Andrei, Ph.D., Board of Governors professor in Rutgers' Department of Physics and Astronomy in the School of Arts and Sciences and the study's senior author, said in a statement. “In the past, we couldn't do it.

“This is the reason people thought that one could not make devices like transistors that require switching with graphene because their electrons run wild,” she added.

Graphene is far stronger than steel and is also a great conductor, but when electrons move through it, they do so in straight lines and their high velocity does not change.

“If they hit a barrier, they can't turn back, so they have to go through it,” Andrei said. “People have been looking at how to control or tame these electrons.” 

The researchers created what resembles an optical system by sending voltage through a scanning tunneling microscope that offers 3D views of surfaces at the atomic scale.

The sharp tip created a force field that traps electrons in graphene or modifies their trajectories, similar to the effect a lens has on light rays.

According to Andrei, electrons can easily be trapped and released, providing an efficient on-off switching mechanism.

“You can trap electrons without making holes in the graphene,” she said. “If you change the voltage, you can release the electrons.

“So you can catch them and let them go at will,” she added.

The advancement could pave the way for the ultra-fast transport of electrons with low energy losses in novel systems, including nano-scale transistors. For graphene electronics the components include ultra-fast amplifiers, supercapacitors and ultra-low resistivity wires.

By adding a graphene transistor, researchers can produce all-graphene electronics platforms.

Graphene is also being developed in flat flexible screens and paintable and printable electronic circuits.

The researchers now plan to scale up by putting extremely thin wires called nanowires on top of graphene and controlling the electrons with voltages.

The study was published in Nature Nanotechnology.  

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