Nav: Home

Taming 'wild' electrons in graphene

October 23, 2017

Graphene - a one-atom-thick layer of the stuff in pencils - is a better conductor than copper and is very promising for electronic devices, but with one catch: Electrons that move through it can't be stopped.

Until now, that is. Scientists at Rutgers University-New Brunswick have learned how to tame the unruly electrons in graphene, paving the way for the ultra-fast transport of electrons with low loss of energy in novel systems. Their study was published online in Nature Nanotechnology.

"This shows we can electrically control the electrons in graphene," said Eva Y. Andrei, Board of Governors professor in Rutgers' Department of Physics and Astronomy in the School of Arts and Sciences and the study's senior author. "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."

Now it may become possible to realize a graphene nano-scale transistor, Andrei said. Thus far, graphene electronics components include ultra-fast amplifiers, supercapacitors and ultra-low resistivity wires. The addition of a graphene transistor would be an important step towards an all-graphene electronics platform. Other graphene-based applications include ultra-sensitive chemical and biological sensors, filters for desalination and water purification. Graphene is also being developed in flat flexible screens, and paintable and printable electronic circuits.

Graphene is a nano-thin layer of the carbon-based graphite that pencils write with. It is far stronger than steel and 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."

Her team managed to tame these wild electrons by sending voltage through a high-tech microscope with an extremely sharp tip, also the size of one atom. They created what resembles an optical system by sending voltage through a scanning tunneling microscope, which offers 3-D views of surfaces at the atomic scale. The microscope's sharp tip creates a force field that traps electrons in graphene or modifies their trajectories, similar to the effect a lens has on light rays. Electrons can easily be trapped and released, providing an efficient on-off switching mechanism, according to Andrei.

"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."

The next step would be to scale up by putting extremely thin wires, called nanowires, on top of graphene and controlling the electrons with voltages, she said.
-end-
The study's co-lead authors are Yuhang Jiang and Jinhai Mao, Rutgers postdoctoral fellows, and a graduate student at Universiteit Antwerpen in Belgium. The other Rutgers co-author is Guohong Li, a research associate.

Rutgers University

Related Graphene Articles:

New chemical method could revolutionize graphene
University of Illinois at Chicago scientists have discovered a new chemical method that enables graphene to be incorporated into a wide range of applications while maintaining its ultra-fast electronics.
Searching beyond graphene for new wonder materials
Graphene, the two-dimensional, ultra lightweight and super-strong carbon film, has been hailed as a wonder material since its discovery in 2004.
New method of characterizing graphene
Scientists have developed a new method of characterizing graphene's properties without applying disruptive electrical contacts, allowing them to investigate both the resistance and quantum capacitance of graphene and other two-dimensional materials.
Chemically tailored graphene
Graphene is considered as one of the most promising new materials.
Beyond graphene: Advances make reduced graphene oxide electronics feasible
Researchers have developed a technique for converting positively charged (p-type) reduced graphene oxide (rGO) into negatively charged (n-type) rGO, creating a layered material that can be used to develop rGO-based transistors for use in electronic devices.
The Graphene 2017 Conference connects Barcelona with the international graphene-based industry
This prestigious Conference to be held at the Barcelona International Convention Centre (March 28-31) aims to bring together academia and industry to integrate new graphene technologies into practical applications.
Graphene from soybeans
A breakthrough by CSIRO-led scientists has made the world's strongest material more commercially viable, thanks to the humble soybean.
First use of graphene to detect cancer cells
By interfacing brain cells onto graphene, researchers at the University of Illinois at Chicago have shown they can differentiate a single hyperactive cancerous cell from a normal cell, pointing the way to developing a simple, noninvasive tool for early cancer diagnosis.
Development of graphene microwave photodetector
DGIST developed cryogenic microwave photodetector which is able to detect 100,000 times smaller light energy compared to the existing photedetectors.
Adding hydrogen to graphene
IBS researchers report a fundamental study of how graphene is hydrogenated.

Related Graphene Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Digital Manipulation
Technology has reshaped our lives in amazing ways. But at what cost? This hour, TED speakers reveal how what we see, read, believe — even how we vote — can be manipulated by the technology we use. Guests include journalist Carole Cadwalladr, consumer advocate Finn Myrstad, writer and marketing professor Scott Galloway, behavioral designer Nir Eyal, and computer graphics researcher Doug Roble.
Now Playing: Science for the People

#529 Do You Really Want to Find Out Who's Your Daddy?
At least some of you by now have probably spit into a tube and mailed it off to find out who your closest relatives are, where you might be from, and what terrible diseases might await you. But what exactly did you find out? And what did you give away? In this live panel at Awesome Con we bring in science writer Tina Saey to talk about all her DNA testing, and bioethicist Debra Mathews, to determine whether Tina should have done it at all. Related links: What FamilyTreeDNA sharing genetic data with police means for you Crime solvers embraced...