Friday, March 4, 2011

Probing atomic chicken wire

Under the scanning tunneling microscope, graphene reveals its honeycomb structure made up of rings of carbon atom, visible as small hexagons. The larger hexagons result from an interference process occurring between the graphene and the underlying boron nitride.

Daniel Stolte

Graphene – a sheet of carbon atoms linked in a hexagonal, chicken wire structure – holds great promise for microelectronics. Only one atom thick and highly conductive, graphene may one day replace conventional silicon microchips, making devices smaller, faster and more energy-efficient.

In addition to potential applications in integrated circuits, solar cells, miniaturized bio devices and gas molecule sensors, the material has attracted the attention of physicists for its unique properties in conducting electricity on an atomic level.

Otherwise known as pencil "lead," graphene has very little resistance and allows electrons to behave as massless particles like photons, or light particles, while traveling through the hexagonal grid at very high speeds.

The study of the physical properties and potential applications of graphene, however, has suffered from a lack of suitable carrier materials that can support a flat graphene layer while not interfering with its electrical properties.

Researchers in the University of Arizona's physics department along with collaborators from the Massachusetts Institute of Technology and the National Materials Science Institute in Japan have now taken an important step forward toward overcoming those obstacles.

They found that by placing the graphene layer on a material almost identical in structure, instead of the commonly used silicon oxide found in microchips, they could significantly improve its electronic properties.

Substituting silicon wafers with boron nitride, a graphene-like structure consisting of boron and nitrogen atoms in place of the carbon atoms, the group was the first to measure the topography and electrical properties of the resulting smooth graphene layer with atomic resolution.

The results are published in the advance online publication of Nature Materials.

"Structurally, boron nitride is basically the same as graphene, but electronically, it's completely different," said Brian LeRoy, an assistant professor of physics and senior author of the study. "Graphene is a conductor, boron nitride is an insulator."

"We want our graphene to sit on something insulating, because we are interested in studying the properties of the graphene alone. For example, if you want to measure its resistance, and you put it on metal, you're just going to measure the resistance of the metal because it's going to conduct better than the graphene."

Unlike silicon, which is traditionally used in electronics applications, graphene is a single sheet of atoms, making it a promising candidate in the quest for ever smaller electronic devices. Think going from a paperback to a credit card.

"It's as small as you can shrink it down," LeRoy said. "It's a single layer, you'll never get half a layer or something like that. You could say graphene is the ultimate in making it small, yet it 's still a good conductor." ...

via Probing atomic chicken wire.


Mirlen101 said...

I've had this theory for years that there is a sub structure to the universe that is something like a 3D hexagonal structure . Because the hexagonal structure is the most compact formation . My theory was that this invisible structure was what the smallest sub-particles , photons tended to move along . That's partly why neutrinos can go through things like the earth so easily .The hexagonal structure would be like a channel of nothing that particles would bounce through in waves . Sort of like channels of void . Atoms nuclei would cling to their intersections like little black holes . A tiny black hole at the core of all atoms . The same as at the center of galaxies ( but infinitely smaller ! ;-) That's the simplified version . That's my theory and I'm sticking to it ! ;-)

Chicken wire said...

I have the magical effect of Chicken wire, used to make him more flexible in my work.

Mirlen101 said...

Huh ?
Cheng is that you ? ;-)

Cheng said...

It appears size does least with electronic chips. Strips of metal, even gold foil, are many times thicker than the single atom thick graphene.
The hunt is on for the thinest electrically conductive material. Plus, I think very thin metal conductors get hot and fail, like a fuse.

.....“It’s as small as you can shrink it down,” LeRoy said. “It’s a single layer, you’ll never get half a layer or something like that. You could say graphene is the ultimate in making it small, yet it ‘s still a good conductor.”....

Cheng said...

Nope! That's me down there. I don't get it either.