Graphene: Unravelling the secrets of a magic material

Oct 15, 2009
Image: the islands of carbon form geodesic dome-like structures resembling Cornwall's Eden Project

UCL researchers are helping to unlock the secrets of a material that could ultimately be used in a new generation of electronic devices.

Graphene is a sheet of carbon just one atom thick - the thinnest known material in the universe and the strongest ever measured.

It is 200 times stronger than steel and can carry one million times more than .

These properties give graphene a number of potential new applications, such as its use in the circuitry of faster computers or more powerful mobile phones, but graphene sheets are difficult and expensive to produce.

Professor Dario Alfč and Dr Monica Pozzo (UCL Earth Sciences) are part of a group trying to understand and characterise the mechanisms for the growth of graphene for one particular method of production.

The method, known as Chemical Vapour Decomposition, involves sending hydrocarbon molecules to an iridium surface that is heated between room temperature and 1000 degrees.

When they hit the surface these molecules loose their hydrogen atoms, which fly into space, leaving the remaining carbon atoms sticking to the iridium, where they start to self-assemble in small ‘nano-structures’. The nano-structures eventually develop into fully formed graphene sheets.

Professor Alfč, Dr Pozzo and their colleagues led by Dr Alessandro Baraldi and Dr Silvano Lizzit at ELETTRA, the Synchrotron light laboratory in Trieste, Italy, have begun to unravel how that process takes place, and thus how it might be controlled.

Professor Alfč said: “This method to grow graphene is well known; however, the mechanism that takes us from a carbon-covered surface to the formation of a fully formed graphene sheet is yet to be understood.

“We discovered that the growth of graphene starts with the formation of small islands of carbon with an unusual dome structure, in which only the atoms at the perimeter are bound to the iridium substrate while the central detach from it, making the island bulge upwards at the centre.

“The structure resembles that of the Eden Project building in Cornwall. We also found that the size of these ‘geodesic nanodomes’ depended on the temperature of the iridium substrate, and the manipulation procedure, suggesting possible routes to control the size of sheets at the nanoscale.

“These could be used in the future as building blocks for new generation electronic circuits, for example to make much faster computers, or mobile phones sending data at much higher rates.”

Provided by University College London (news : web)

Explore further: Competition for graphene: Researchers demonstrate ultrafast charge transfer in new family of 2-D semiconductors

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User comments : 8

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poi
not rated yet Oct 15, 2009
The method, known as Chemical Vapour Decomposition

imho it's "deposition"
but since it looks british, is this their translation of it? much like "responsibility" in AEnglish is "liability" for French.
Birthmark
not rated yet Oct 15, 2009
Interesting, when is it suspected to hit the markets, 20 years, 30 years from now? How vast will this transform things?
Au-Pu
not rated yet Oct 16, 2009
I fail to see "poi's" point.
The description of decomposition appears to be correct if we understand that decomposition means to break up or disintegrate, which is what occurs when the hydrogen atoms are driven out of the molecule which allows the carbon residue to deposit on the iridium surface.
Of course decompose has its own french origins and the meaning is the same in both French and English.
But if this was an exercise in pedantry then it was rather futile and non constructive. Pedant also has French origins and the meanings are consistent in both languages. I fail to see the relevance in any words origin and or the consistency of meaning across languages with respect to the work being reported on. The explanation made the process that was being described clear.
"Birthmark's" question was far more relevant.
An estimate of time to market would be of interest.
Critical_Mass
not rated yet Oct 17, 2009
More importantly is this method a cost-effective way of producing graphene sheets, especially since there is no mention of the uniformity/quality of the graphene sheets.
Despite the coolness of spraying hydrocarbons on iridium and getting graphene, when you're thirsty it's better to pour a glass of water than open your mouth in a rainstorm.
lasikexpert
5 / 5 (1) Oct 18, 2009
In 20 years almost all of the advances in medicine will be based on nanotechnology.
vantomic
not rated yet Oct 19, 2009
poi is correct. there is actually not a process called chemical vapor decomposition. I'm sure its just a typo, but it is chemical vapor deposition.
El_Nose
not rated yet Oct 19, 2009
The usage of the word deposition comes from deposit -- to place, put, or leave an object, often in a safe place.
danman5000
not rated yet Oct 19, 2009
When they hit the surface these molecules loose their hydrogen atoms,

I can't believe how the vast majority of the people on the internet don't understand lose vs loose. Lose = loss of something, loose = not tight. Pretty soon this mixup is going to become the new standard, like how "lol" is turning into its own word.

On a more related note, as people have noted above it is in fact "Chemical Vapor Deposition" not decomposition. Hopefully both of these were typos.