Large-area graphene on copper may lead to faster computers, electronics

May 8th, 2009 - 3:05 pm ICT by ANI  

Washington, May 8 (ANI): The development of large-area graphene using copper may pave the way for faster computers and electronics, according to scientists and engineers at The University of Texas at Austin.

Graphene, an atom-thick layer of carbon atoms bonded to one another in a “chickenwire” arrangement of hexagons, holds great potential for nanoelectronics, including memory, logic, analog, opto-electronic devices and potentially many others.

“Graphene could lead to faster computers that use less power, and to other sorts of devices for communications such as very high-frequency (radio-frequency-millimeter wave) devices. Graphene might also find use as optically transparent and electrically conductive films for image display technology and for use in solar photovoltaic electrical power generation,” said Professor and physical chemist Rod Ruoff, one of the corresponding authors on the study.

He added: “There is a critical need to synthesize graphene on silicon wafers with methods that are compatible with the existing semiconductor industry processes. Doing so will enable nanoelectronic circuits to be made with the exceptional efficiencies that the semiconductor industry is well known for.”

For the study, the researchers grew graphene on copper foils whose area was limited only by the furnace used.

And, for the first time, they showed that centimetre-square areas could be covered almost entirely with monolayer graphene, with a small percentage (less than five percent) of the area being bi-layer or tri-layer flakes.

The team then created dual-gated field effect transistors with the top gate electrically isolated from the graphene by a very thin layer of alumina, to determine the carrier mobility.

The devices showed that the mobility, a key metric for electronic devices, is significantly higher than that of silicon, the principal semiconductor of most electronic devices, and comparable to natural graphite.

Ruoff said: “We used chemical-vapor deposition from a mixture of methane and hydrogen to grow graphene on the copper foils. The solubility of carbon in copper being very low, and the ability to achieve large grain size in the polycrystalline copper substrate are appealing factors for its use as a substrate –along with the fact that the semiconductor industry has extensive experience with the use of thin copper films on silicon wafers.

“By using a variety of characterization methods we were able to conclude that growth on copper shows significant promise as a potential path for high quality graphene on 300-millimeter silicon wafers.”

A research article on this study has been published online in the journal Science. (ANI)

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