Physicists develop scalable method for making graphene

Feb 25, 2011 by Evan Lerner
Physicists develop scalable method for making graphene
Copper-grown graphene circuits. (Photo: Zhengtang Luo)

(PhysOrg.com) -- New research from the University of Pennsylvania demonstrates a more consistent and cost-effective method for making graphene, the atomic-scale material that has promising applications in a variety of fields, and was the subject of the 2010 Nobel Prize in Physics.

As explained in a recently published study, a Penn research team was able to create high-quality graphene that is just a single atom thick over 95% of its area, using readily available and manufacturing processes that can be scaled up to industrial levels.

“I’m aware of reports of about 90%, so this research is pushing it closer to the ultimate goal, which is 100%,” said the study’s principal investigator, A.T. Charlie Johnson, professor of physics. “We have a vision of a fully industrial process.”

Other team members on the project included postdoctoral fellows Zhengtang Luo and Brett Goldsmith, graduate students Ye Lu and Luke Somers and undergraduate students Daniel Singer and Matthew Berck, all of Penn’s Department of Physics and Astronomy in the School of Arts and Sciences.

The group’s findings were published on Feb. 10 in the journal Chemistry of Materials.

Graphene is a chicken-wire-like lattice of carbon atoms arranged in thin sheets a single atomic layer thick. Its unique physical properties, including unbeatable electrical conductivity, could lead to major advances in solar power, energy storage, computer memory and a host of other technologies. But complicated manufacturing processes and often-unpredictable results currently hamper graphene’s widespread adoption.

Producing graphene at industrial scales isn’t inhibited by the high cost or rarity of natural resources – a small amount of graphene is likely made every time a pencil is used – but rather the ability to make meaningful quantities with consistent thinness.

One of the more promising manufacturing techniques is CVD, or chemical vapor deposition, which involves blowing methane over thin sheets of metal. The carbon in methane form a thin film of graphene on the metal sheets, but the process must be done in a near vacuum to prevent multiple layers of carbon from accumulating into unusable clumps.

The Penn team’s research shows that single-layer-thick graphene can be reliably produced at normal pressures if the metal sheets are smooth enough.

“The fact that this is done at atmospheric pressure makes it possible to produce graphene at a lower cost and in a more flexible way,” Luo, the study’s lead author, said.

Whereas other methods involved meticulously preparing custom copper sheets in a costly process, Johnson’s group used commercially available copper foil in their experiment.

“You could practically buy it at the hardware store,” Johnson said.

Other methods make expensive custom copper sheets in an effort to get them as smooth as possible; defects in the surface cause the graphene to accumulate in unpredictable ways. Instead, Johnson’s group “electropolished” their copper foil, a common industrial technique used in finishing silverware and surgical tools. The polished foil was smooth enough to produce single-layer graphene over 95% of its surface area.

Working with commercially available materials and chemical processes that are already widely used in manufacturing could lower the bar for commercial applications.

“The overall production system is simpler, less expensive, and more flexible” Luo said.

The most important simplification may be the ability to create graphene at ambient pressures, as it would take some potentially costly steps out of future graphene assembly lines.

“If you need to work in high vacuum, you need to worry about getting it into and out of a vacuum chamber without having a leak,” Johnson said. “If you’re working at atmospheric pressure, you can imagine electropolishing the copper, depositing the onto it and then moving it along a conveyor belt to another process in the factory.”

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User comments : 10

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stealthc
1.8 / 5 (5) Feb 25, 2011
it's dandy that it could be that simple, but the prices of cpu's will never drop, not without competition, and for that it depends entirely how greedy these people are. The invention isn't enough anymore, not with how the corporate world withholds things and milks us for it.
Quantum_Conundrum
4.2 / 5 (5) Feb 25, 2011
Eventual applications in computers, electronics, and ultra-strong composite materials will be amazing...

200 times the breaking strength of steel!

We can imagine ultra-light aircraft, and possibly air ships as fuels are running out in the future.
Quantum_Conundrum
2.8 / 5 (6) Feb 25, 2011
it's dandy that it could be that simple, but the prices of cpu's will never drop, not without competition, and for that it depends entirely how greedy these people are. The invention isn't enough anymore, not with how the corporate world withholds things and milks us for it.


Well, see, you may be right, but the thing is once computers reach a certain insanely powerful level, there will be no motivation to buy a new computer except when the old one breaks. Manufacturers will be desperate for a sale, or will be REQUIRED to diversify. Either way, prices would be forced to come down because they would have to do "something" to encourage people to buy a new computer.

People aren't going to buy a new computer every few years when they have a thousand processor cores. The "need" for more processing power in a PC died a few years ago. Now we have more processing power because we like toys and games and video on computers.
FrankHerbert
1.3 / 5 (55) Feb 25, 2011
it's dandy that it could be that simple, but the prices of cpu's will never drop, not without competition, and for that it depends entirely how greedy these people are. The invention isn't enough anymore, not with how the corporate world withholds things and milks us for it.


Seriously? You can buy what would have been considered a super computer 5 years ago for around $1000. How cheap do you think they should be? I am no friend of capitalism but you're being somewhat ridiculous. Since cars have been around for over 100 years I guess we should be able to pick them up for $20 at the corner store.
Bonkers
5 / 5 (2) Feb 25, 2011
Frank - don't feed the trolls... we all know that CPU costs fall with Moore's law, and that its a mature diverse market working well. We milk them half the time, if you look at DRAM losses, AMD losses etc.
Lordjavathe3rd
not rated yet Feb 25, 2011
1 atom thick?! I hadn't realized we were so close to subatomic computing.
AZJay
5 / 5 (1) Feb 25, 2011
"Provided by Pennsylvania State University"
Um, well, recall University of Pennsylvania is in Philadelphia, quite different place from State College...
Parsec
3 / 5 (1) Feb 25, 2011
Every reduction in price and increase in speed has resulted in a spread of applicable applications that had been out of boue, because 'obviously everything that can be invented as already been invented. To those who think computers are as fast as they need to go (QC), I refer you to the well known proposal at the turn of the 20th century to close the patent office because it was obvious that everything that could be invented had already been invented, and thus the patent office was just a waste of the taxpayers money.
that_guy
4.5 / 5 (2) Feb 25, 2011
To those who think computers are as fast as they need to go (QC)


QC has a point that you are completely ignoring for semantics. Faster computers will always be great, but 10 years ago, computers were so slow, that you were clawing for a new one 2 years later. Now if you have a computer that is 2 or 3 years old, it's not a big deal unless you're a major gamer. There is not as much pressure because the increased usefulness of speed is diminishing as it computers get faster. There's certainly more to get out, but it IS losing SOME importance to go faster.

Have you noticed that game consoles have ever longer life cycles and improvements that are less and less noticable?

As for price, my phone is 4 times faster than a 10 year old computer and costs a third as much out of contract.

PS, I gave you a 3 because you had good points outside of your misfire on QC
Decimatus
5 / 5 (1) Feb 28, 2011
In terms of productivity, computers are sitting pretty right now, but it only takes 1-2 new key applications to turn that on it's head.

Facebook turning into a form of virtual reality would be one such key application that would essentially force the world to need ever faster computers.

And of course, gamers will be yearning for faster computers until graphics and physics are both seamlessly represented within gigantic game worlds.

Moores Law will march on into the forseeable future, and Graphene is one piece that will make it happen.