backtop


Print 12 comment(s) - last by Goty.. on Jul 14 at 10:29 AM

Measurement is core to understanding graphene according to researcher

Graphene is one of the materials that is the subject of considerable research and has the potential to be used in a variety of applications. One of the major applications of the material could be in computer CPUs.

Researchers say that the properties of graphene could allow the construction of computer processors that run at 1000GHz frequencies. The material also has potential applications in sensing instruments, chemical sensors, and other biosensors thanks to its low capacitance, which makes a very low signal to noise ratio.

Researcher N.J. Tao from the Biodesign Institute at Arizona State University says that graphene is comprised of a two-dimensional honeycomb structure of carbon atoms and is very strong and versatile. According to Tao, graphene is roughly 200 times stronger than steel and is very light. A sheet of graphene one atom thick and large enough to cover an entire football field would weigh under a gram.

The excitement about graphene isn’t about its strength of lightweight nature, but about its unusual electronic properties. The Biodesign Institute at Arizona State University explains that graphene has a unique and outstanding ability to allow electricity to flow through its material with little impedance.

Tao has been able to measure the quantum capacitance of graphene, which he stresses is an essential part of understanding  of graphene and its use in microprocessors and other applications. The quantum capacitance of a material is the result of the Pauli exclusion principal that states two fermions can't occupy the same location at the same time. That means that when one quantum state inside graphene is filled, fermions are forced to occupy successively higher energy states.

Tao explains the process, "it’s just like in a building, where people are forced to go to the second floor once the first level is occupied."

Tao's study placed two electrodes on to a graphene structure and voltage was applied across the materials two-dimensional surface with a third gate electrode. The ability of graphene to store charge according to the laws of quantum capacitance were directly measured and did not conform to predictions of the behavior of graphene.

One possible future use for graphene in biosensor applications involves putting antibodies onto the surface of graphene to study the interaction of the antibodies with specific antigens. The sensor would be able to detect individual binding events given a suitable sample. The material could also be used in the future as an ultracapacitor to store massive amounts of energy form solar or wind power plants.

Tao said, "You can imagine an atomic sheet, cut into different shapes to create different device properties."


Comments     Threshold


This article is over a month old, voting and posting comments is disabled

Misunderstanding
By Goty on 7/13/2009 8:35:03 AM , Rating: 5
quote:
Electrons have been shown to behave as massless particles when they pass through graphene similar to how photons move. Electrons move through graphene without scattering.


DT needs to hire a physicist to write some of these articles. =P

These two statements seem to imply that photons do not scatter (whether off of one another or off of massive particles), which is simply false.




RE: Misunderstanding
By MrPoletski on 7/13/2009 8:58:08 AM , Rating: 2
not to mention:
quote:
The ability of graphene to store charge according to the laws of quantum capacitance were directly measured and did not conform to predictions of the behavior of graphene.


That's it? that's all we get? "it wasn't what we thought"

pardon me for asking how the hell it did behave then?!?

and as for the scattering, I can only assume that they mean that photons do not scatter when thrown, individually, into a perfect vacuum (which is also impossible). Anyway, 'moving through a material without scattering like massless particles' isn't specific enough. Do they mean that the free electron gas inside graphene acts as a superfluid? it can't or else it would be superconductive.

where the hell is this scientists webpage?


RE: Misunderstanding
By tdktank59 on 7/13/2009 9:38:14 AM , Rating: 2
I have to agree here... That just made me want to go on a rampant spree of doing something unmentionable to the author of this article...

At least say you have no idea what it is dammit... Don't give us false hope the number may be on a better site that gives it users the actual answers...


RE: Misunderstanding
By MrPoletski on 7/13/2009 10:56:18 AM , Rating: 2
I found this:
quote:
http://adsabs.harvard.edu/abs/2007arXiv0707.2242F


I don't know if it's the same study, but it sounds like it might be.


RE: Misunderstanding
By Kanji on 7/13/2009 1:13:50 PM , Rating: 2
Nope not the same study.

quote:
Researcher N.J. Tao from the Biodesign Institute at Arizona State University says...


RE: Misunderstanding
By mxyztplk on 7/13/2009 3:07:36 PM , Rating: 2
From a considerably better article:

In Tao's experiments, graphene's ability to store charge according to the laws of quantum capacitance, were subjected to detailed measurement. The results show that graphene's capacitance is very small. Further, the quantum capacitance of graphene did not precisely duplicate theoretical predictions for the behavior of ideal graphene. This is due to the fact that charged impurities occur in experimental samples of graphene, which alter the behavior relative to what is expected according to theory.


http://www.nanowerk.com/news/newsid=11570.php


Here we go...
By retrospooty on 7/13/2009 9:11:08 AM , Rating: 2
Pedantic rant in 3...2...1...

=)




RE: Here we go...
By PlasmaBomb on 7/13/2009 9:57:41 AM , Rating: 2
Nice try, you were only 36 minutes and 5 seconds late...


RE: Here we go...
By retrospooty on 7/13/2009 12:14:59 PM , Rating: 2
LOL - I know, I missed the first post, but I figured the pedantic rants would continue anyhow...


RE: Here we go...
By Goty on 7/14/2009 10:29:29 AM , Rating: 2
It's not pedantic if the author is disseminating misleading information due to his lack of understanding about the topic.

(No offense, Shane)


Signal to Noise Ratio s/b Low???
By Kulamata on 7/13/2009 5:06:45 PM , Rating: 3
I suspect that the purportedly desirable low signal to noise ratio is in error; a high signal to noise (high signal, low noise) ratio is preferable.

I used to regard DailyTech as reliable, with the exception of the wild excursions off the rails of Asher... but lately there have been several blunders.




By rvd2008 on 7/14/2009 12:30:51 AM , Rating: 2
my sensors are low on dt signal today.\
:-)
Very lame by any standards, I wonder is it really worth to open this website?


"DailyTech is the best kept secret on the Internet." -- Larry Barber

Related Articles













botimage
Copyright 2014 DailyTech LLC. - RSS Feed | Advertise | About Us | Ethics | FAQ | Terms, Conditions & Privacy Information | Kristopher Kubicki