A Tiny Defect That May Create Smaller, Faster Electronics

Mar 31, 2010
An artist's conception of a row of intentional molecular defects in a sheet of graphene. The defects effectively create a metal wire in the sheet. This discovery may lead to smaller yet faster computers in the future. Credit: Y. Lin, USF

(PhysOrg.com) -- When most of us hear the word 'defect', we think of a problem that has to be solved. But a team of researchers at the University of South Florida (USF) created a new defect that just might be a solution to a growing challenge in the development of future electronic devices.

The team lead by USF Professors Matthias Batzill and Ivan Oleynik, whose discovery was published yesterday in the journal , have developed a new method for adding an extended to graphene, a one-atom-thick planar sheet of that many believe could replace silicon as the material for building virtually all electronics.

It is not simple to work with graphene, however. To be useful in electronic applications like , small defects must be introduced to the material. Previous attempts at making the necessary defects have either proved inconsistent or produced samples in which only the edges of thin strips of graphene or graphene possessed a useful defect structure. However, atomically-sharp edges are difficult to create due to natural roughness and the uncontrolled chemistry of dangling bonds at the edge of the samples.

The USF team has now found a way to create a well-defined, extended defect several atoms across, containing octagonal and pentagonal carbon rings embedded in a perfect graphene sheet. This defect acts as a quasi-one-dimensional metallic wire that easily conducts electric current. Such defects could be used as metallic or elements of device structures of all-carbon, atomic-scale electronics.

So how did the team do it? The experimental group, guided by theory, used the self-organizing properties of a single-crystal nickel substrate, and used a metallic surface as a scaffold to synthesize two graphene half-sheets translated relative to each other with atomic precision. When the two halves merged at the boundary, they naturally formed an extended line defect. Both scanning tunneling microscopy and electronic structure calculations were used to confirm that this novel one-dimensional carbon defect possessed a well-defined, periodic atomic structure, as well as metallic properties within the narrow strip along the defect.

This tiny wire could have a big impact on the future of computer chips and the myriad of devices that use them. In the late 20th century, computer engineers described a phenomenon called Moore's Law, which holds that the number of transistors that can be affordably built into a computer processor doubles roughly every two years. This law has proven correct, and society has been reaping the benefits as computers become faster, smaller, and cheaper. In recent years, however, some physicists and engineers have come to believe that without new breakthroughs in new materials, we may soon reach the end of Moore's Law. As silicon-based transistors are brought down to their smallest possible scale, finding ways to pack more on a single processor becomes increasingly difficult.

Metallic wires in may help to sustain the rate of microprocessor technology predicted by Moore's Law well into the future. The discovery by the USF team, with support from the National Science Foundation, may open the door to creation of the next generation of electronic devices using novel materials. Will this new discovery be available immediately in new nano-devices? Perhaps not right away, but it may provide a crucial step in the development of smaller, yet more powerful, in the not-too-distant future.

Explore further: Tiny graphene drum could form future quantum memory

More information:
Materials Simulation Lab at University of South Florida: msl.cas.usf.edu
Nanophysics and Surface Science Laboratory at University of South Florida: shell.cas.usf.edu/~mbatzill/

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User comments : 8

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Feldagast
2 / 5 (3) Mar 31, 2010
Sort of like playing Tetris with graphene and other materials, drop a line of graphene then one of nickle then a pnp material then some other and you have a transistor. Just would have to make sure that darn music wasn't playing.
moj85
3 / 5 (3) Mar 31, 2010
This article doesn't explain WHY having the defect helps. Or, why this would be the next step in maintaining Moore's Law. Does the defect allow electrical conductance? Does it allow the semiconductors to be even smaller than without the defect? ...
baudrunner
1 / 5 (11) Mar 31, 2010
This article doesn't explain WHY having the defect helps. Or, why this would be the next step in maintaining Moore's Law. Does the defect allow electrical conductance? Does it allow the semiconductors to be even smaller than without the defect? ...

moj85... the 85 is for IQ, no? In order to appreciate the content of the article, it helps to have some background in science, electronics, physics, etc. Enjoy the site, read all you want, but don't embarass yourself by posting comments.
gmurphy
5 / 5 (8) Mar 31, 2010
baudrunner: it is a weak mind that mocks the ignorance of others, mojo85 had a question and you derided him for his honesty, perhaps the rarefied air, up there in your lofty intellectual heights has reduced the oxygen getting to your brain, preventing you from remembering a time when you too had to ask questions?
Parsec
not rated yet Mar 31, 2010
These posts remind me how my own posts read when I am trying to show how smart I am. I am making a mental note to try to avoid that in the future cause 'it's kinda stinky'.

The article DID explain that the defect conducts electricity well. However, so does graphene. I have confidence that the defect would allow device development because the obstacle could be used to 'bounce' or alter the ballistic electron's in the graphene. I am disappointed that the article didn't go into that, because that would be quite interesting.
jcettison
5 / 5 (3) Mar 31, 2010
This article doesn't explain WHY having the defect helps. Or, why this would be the next step in maintaining Moore's Law. Does the defect allow electrical conductance? Does it allow the semiconductors to be even smaller than without the defect? ...

moj85... the 85 is for IQ, no? In order to appreciate the content of the article, it helps to have some background in science, electronics, physics, etc. Enjoy the site, read all you want, but don't embarass yourself by posting comments.


Post reported for abuse.

In the future, perhaps you should spell the word "embarrass" correctly -lest you embarrass yourself.
PinkElephant
not rated yet Mar 31, 2010
The article DID explain that the defect conducts electricity well. However, so does graphene.
That's the first thought that popped into my mind, as well. It's great to have "metallic" wires conducting well, but when they're embedded in another well-conducting medium, the parasitic losses from such circuits would be catastrophic.

Now, if they could also engineer another type of defect that produces extremely poor conduction, and tightly surround the 'wire' with such an insulator, then we'll be talking real-life applications.

Another thing I wonder about, is how scalable this particular technique can be. When you need to create a web of billions of wires, turning at sharp angles and passing over/under each other (within a single sheet of graphene... uh... ??), it doesn't seem the self-organizing substrate-driven growth strategy could be all that effective.
lewando
1 / 5 (4) Mar 31, 2010
@moj85: Don't be intimidated by people who don't have a dog to kick. Or who have recently run out of Viagra.

With regard to the article, I am wondering how standard equations that calculate characteristic impedance of transmission lines hold up for atomic level structures.