Next generation devices get boost from graphene research

Jan 22, 2010
Next generation devices get boost from Penn State research
This graphene wafer contains more than 22,000 devices and test structures. Provided by the EOC.

(PhysOrg.com) -- Researchers in the Electro-Optics Center (EOC) Materials Division at Penn State have produced 100 mm diameter graphene wafers, a key milestone in the development of graphene for next generation high-power, high-frequency electronic devices.

Graphene is the two-dimensional form of graphite and consists of tightly bound in a hexagonal arrangement resembling chicken wire. Thanks to the ability of an electron to move at 1/300th the speed of light through (significantly faster than silicon), graphene is a candidate material for many high-speed computing applications in the multibillion-dollar semiconductor device industry.

The Penn State EOC is a leading center for the synthesis of graphene materials and graphene-based devices. Using a process called silicon sublimation, EOC researchers David Snyder and Randy Cavalero thermally processed wafers in a high temperature furnace until the silicon migrated away from the surface, leaving behind a layer of carbon that formed into a one- to two-atom-thick film of graphene on the wafer surface. The EOC wafers were 100mm in diameter, the largest diameter commercially available for silicon carbide wafers, and exceeded the previous demonstration of 50mm.

According to EOC materials scientist Joshua Robinson, Penn State is currently fabricating field effect transistors on the 100 mm graphene wafers and will begin transistor performance testing in early 2010. A further goal is to improve the speed of electrons in graphene made from silicon carbide wafers to closer to the theoretical speed, approximately 100 times faster than silicon. That will require improvements in the material quality, says Robinson, but the technology is new and there is plenty of room for improvements in processing.

In addition to silicon sublimation, EOC researchers Joshua Robinson, Mark Fanton, Brian Weiland, Kathleen Trumbull and Michael LaBella are developing the synthesis and device fabrication of graphene on silicon as a means to achieve diameters exceeding 200mm, a necessity for integrating graphene into the existing semiconductor industry. With the support of the Naval Surface Warfare Center in Crane, Ind., EOC researchers are initially focusing on graphene materials to improve the transistor performance in various radio frequency (RF) applications.

With its remarkable physical, chemical and structural properties, graphene is being studied worldwide for electronics, displays, solar cells, sensors, and hydrogen storage. Graphene has the potential to enable terahertz computing, at processor speeds 100 to 1,000 times faster than . For a material that was first isolated only five years ago, is getting off to a fast start.

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flaredone
not rated yet Jan 23, 2010
What makes graphene so unique? We can illustrate graphite lattice by model of stacked sieves composed of wire mesh, which are vetted by water surface, analogous to Fermi surface of electrons inside of graphite. In stacked state, pile of meshes can hold a significant amount of water between its wires. But when we remove one layer of mesh, the amount of watter attached on it would decrease significantly because of higher surface/volume ratio.

http://tinyurl.com/yaw5bkf

Due the higher pressure inside of graphene orbitals the electrons behave like chaotic superfluid inside of hole stripes in HT superconductors in over-doped state. With compare to superconductors, the pressure of free orbital surface on graphene layer isn't still sufficient for formation of fully chaotic system of electrons, but low energy excitations would propagate here in much higher speed, then electrons inside of common metals and they move in ballistic way.
flaredone
not rated yet Jan 23, 2010
I presume, the balistic transport of electrons in graphene has its analogy in the way, how fresh cold snow crackles and crunches under feet. The molecules of water are polar and they're forming thin layer of molten water at the surface of ice crystal. In this layer water molecules are moving under high pressure in waves, which leads to phenomena known as ice regelation.

http://en.wikiped...gelation

In this way, the cracking of snow crunched demonstrates, how ballistic motion of electrons in graphene could appear in fluid analogy. The low temperature quantum analogy of ice regelation is so-called supersolidity phenomena.