device and infrared measurement.
Credit: UCSD
Posted on 08/07/2008 12:39:51 PM PDT by neverdem
Using one of the world’s most powerful sources of man-made radiation, physicists from UC San Diego, Columbia University and Lawrence Berkeley National Laboratory have uncovered new secrets about the properties of graphene—a form of pure carbon that may one day replace the silicon in computers, televisions, mobile phones and other common electronic devices.
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| A schematic of the graphene device and infrared measurement. Credit: UCSD |
Graphene—a single layer of carbon atoms arranged in a honeycombed lattice—has a number of advantages over silicon. Because it is an optically transparent conductor of electricity, graphene could be used to replace current liquid crystal displays that employ thin metal-oxide films based on indium, a rare metal that is becoming increasingly expensive and likely to be in short supply within a decade. The problem for scientists is that not much is known about its optical and electronic properties because graphene, which was discovered only four years ago, has resisted traditional forms of spectroscopy.
In this week’s advance online publication of the journal Nature-Physics, the physicists report that they used the Advanced Light Source at the Berkeley lab—one of the most powerful and versatile sources of electromagnetic radiation, from the infrared to x-ray region, in the world—to reveal some of those secrets. The researchers said that their study shows that the electrons in graphene strongly interact not only with the honeycomb lattice, but also with each other.
“Infrared and optical experiments are capable of providing some of the most valuable insights into the electronic properties of materials, including interactions between electrons in a material,” said Dimitri Basov, a professor of physics at UC San Diego who headed the project. “But it was extremely difficult to measure the absorption of light in a single monolayer of graphene, because not much light is absorbed. To do this, we had to start with a very bright light. It was spectroscopy to the extreme.”
The radiation from the Advanced Light Source, or ALS, is about 100 million times brighter than that from the most powerful X-ray tube, the source used in a dentist's machine. High brightness means that the radiation is highly concentrated and many photons per second can be directed onto a tiny area of a material.
Just as dentists use x rays to see inside your gums, scientists use the ALS’s radiation—generated by accelerating electrons around a circular racetrack at close to the speed of light—to look inside materials.
“It took some difficult experimental work to make this measurement,” said Basov. “It was by far the most complicated measurement we have ever done.”
Zhiqiang Li, a UCSD physics graduate student in Basov’s group, was the first author of the paper. Other principal investigators involved in the discovery were Michael Martin, staff scientist at the Berkeley laboratory’s ALS; Philip Kim, an associate professor of physics at Columbia University; and Horst Stormer, a professor of physics at Columbia and winner of the 1998 Nobel Prize in Physics.
Funding for the project was provided by the U.S. Department of Energy.
Media Contact: Kim McDonald, 858-534-7572
Comment: Dimitri Basov, 858-822-1211
I believe this is it.
That’s all great, but what does it’s footprint look like?
This doesn't make sense. The electrons are part of the graphene atoms, and the graphene atoms covalently bonded to each other (i.e. sharing electrons) are what make up the "honeycomb" lattice. How could the electrons possibly NOT interact with each other? If they weren't interacting with each other, there wouldn't be a lattice.
I thought they were calling it algorium?
Broccoli could reverse the heart damaging effects of diabetes
Drexel opens new institute to study plasma
FReepmail me if you want on or off my health and science ping list.
Oooooo CARBON - dat BAD!!
bump for later
Don’t you realize that the layer of graphene on monitors will destroy what’s left of the polar bear population! Carbon is poison! Poison I tell you! ... Quick somebody call Al!
How about a graphene condom? They could call them mano-tubes.
At last.
I always wondered what a Carbon Footprint actually looked like. Interestingly, it looks like it has 5 toes when I would have expected six for a honeycomb structure.
Never work. I know that condoms cannot stand one little prick.
L.P.
Thanks for posting this.
Here’s another item that may be worth its own science thread (if it hasn’t already been posted):
A study published in tomorrow’s Science shows that our Solar System may be more special than thought after all.
http://www.sciencemag.org/cgi/content/abstract/321/5890/814
Gas Disks to Gas Giants: Simulating the Birth of Planetary Systems
Edward W. Thommes,1,2* Soko Matsumura,2 Frederic A. Rasio2 The ensemble of now more than 250 discovered planetary systems displays a wide range of masses, orbits and, in multiple systems, dynamical interactions. These represent the end point of a complex sequence of events, wherein an entire protostellar disk converts itself into a small number of planetary bodies. Here, we present self-consistent numerical simulations of this process, which produce results in agreement with some of the key trends observed in the properties of the exoplanets. Analogs to our own solar system do not appear to be common, originating from disks near the boundary between barren and (giant) planet-forming.
And not only carbon, but PURE carbon.
To the watermelons, more lethal than mercury.
Thanks a bunch!
Yikes!
Kryptonite!
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