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Nanotechnology Spotlight

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Showing Spotlights 105 - 106 of 106 in category Graphene (newest first):

 

'Cool' graphene might be ideal for thermal management in nanoelectronics

grapheneThere has been quite a buzz about graphene, a single atomic layer thick, plane of carbon atoms arranged in a honeycomb lattice. Discovered only in 2004, graphene exhibits many exotic properties and currently is considered the most exciting new material system among nanotechnology researchers. This rising star in material science exhibits remarkable electronic properties that qualify it for applications in future optoelectronic devices. In a first experimental study of the thermal conductivity of single-layer graphene, researchers found that on top of many unique electronic properties, graphene also is an extraordinary good heat conductor. Measurements revealed that graphene's near room temperature thermal conductivity, which is in the range from 3500-5300 W/mK, is much higher than that of diamond, the best bulk crystal heat conductor. It appears that the thermal conductivity of graphene is larger than conventionally accepted experimental values reported for individual suspended carbon nanotubes (CNTs) and corresponds to the upper bound of the highest values reported for single-wall CNT bundles. The superb thermal conduction property of graphene is beneficial for its proposed electronic applications and establishes graphene as an excellent material for thermal management also in optoelectronics, photonics and bioengineering.

Posted: Feb 21st, 2008

Nanotechnology researchers go ballistic over graphene

Carbon comes in many different forms, from the graphite found in pencils to the world's most expensive diamonds. In 1980, we knew of only three basic forms of carbon, namely diamond, graphite, and amorphous carbon. Then, fullerenes and carbon nanotubes were discovered and all of a sudden that was where nanotechnology researchers wanted to be. Recently, though, there has been quite a buzz about graphene. Discovered only in 2004, graphene is a flat one-atom thick sheet of carbon. Existing forms of carbon basically consist of sheets of graphene, either bonded on top of each other to form a solid material like the graphite in your pencil, or rolled up into carbon nanotubes (think of a single-walled carbon nanotube as a graphene cylinder) or folded into fullerenes. Physicists had long considered a free-standing form of planar graphene impossible; the conventional wisdom was that such a sheet always would roll up. Initially using such high-tech gadgets like pencils and sticky tape to strip chunks of graphite down to layers just one atom thick, the process has now been refined to involve more expensive instruments such as electron beam and atomic force microscopes. Despite being isolated only three years ago, graphene has already appeared in hundreds of papers. The reason scientists are so excited is that two-dimensional crystals (it's called 2D because it extends in only two dimensions - length and width; as the material is only one atom thick, the third dimension, height, is considered to be zero) open up a whole new class of materials with novel electronic, optical and mechanical properties.

Posted: Aug 8th, 2007