Archive for the ‘Materiales’ Category

Graphene Emerging as the Miracle Material of the New Millenium


Move over, silicon: graphene is ready for its closeup. Discovered just a few years ago, graphene is a sheet of graphite the thickness of just one atom. It can be processed like silicon to make electronic devices, which makes it easier to manipulate than the current “it” material, carbon nanotubes. Without the breakdown problems that beset silicon at the nanoscale, graphene is bringing the dream of a molecule-sized computer closer to reality.


FUENTE – CleanTechnica – 26/06/09

Graphene was discovered in 2004 by researchers at the University of Manchester and Chernogolovka, Russia. It can be found in flakes of graphite, a layered compound familiar to anyone who has used a pencil. In powder form graphite is a lubricant. Along with pencils, graphite is used to make steel, batteries, and brake linings.

Graphene to Copper: Buh-Bye

One potential roadblock to the use of graphene in mass production is the instability of graphene flakes. Researchers at Georgia Tech foresee a solution: “growing” graphene sheets on silicon carbide. According to the researchers, synthetic graphite sheets have the potential to achieve a higher level of quality, making them an alluring substitute for copper. In fact, they graphene could outperforms copper wire in connecting transistors and other integrated circuits.

Graphene Takes the World By Storm

The Georgia Tech research is just the tip of the graphene iceberg. Research teams at UCLA are also on to a method for the mass production of graphene. Next door at UC Berkeley, reserachers are exploring the “tunable” properties of bilayered graphene through manipulating electrical fields. At the University of Texas at Austin, they’re working on a graphene based mega-battery, and the University of Crete in Greece is also exploring the potential for using graphene to store hydrogen, in combination with carbon nanotubes and lithium ions.

Graphene Compared to Carbon Nanotubes and Silicon

Scratch a graphene researcher, and you’ll find an ex-carbon nanotube fan. Carbon nanotubes are notoriously difficult to manipulate compared to graphene. In terms of the leap from labwork to mass production, carbon nanotubes are also at a disadvantage. While both share a superior ability to conduct electricity, carbon nanotubes require unique steps in processing. In contrast, graphene can be manipulated on silicon carbide, using the familiar steps of silicon processing. As for the advantage over silicon itself, graphene far surpasses silicon on the nanoscale and is capable of much finer processing.

What’s so Green About Graphene?

Graphene-based electronics could lead to a stripped down world in which the size of human fingers is the only limiting factor in the miniaturization of electronic devices. The reduction in e-waste alone is well worth the effort. Georgia Tech researchers report that the electrons in graphene are more than 100 times more mobile than in silicon even at room temperature, reducing the need for energy-sucking temperature controls. At Northwestern University, research teams have identified the chemical key to manipulating graphene-based functions, which could lead to advances in any number of sustainability fields including photovoltaics.

Here’s the clincher: The stunningly eclectic DARPA (the Defense Advanced Research Project Agency) is starting to invest heavily in graphene-based electronics through its Microsystems Technology Office, which is developing graphene-based transistors. With the weight of the defense department behind it, graphene can only go up from here.