IBM clubs nano noise with graphene sandwich
Mayo or may not usurp silicon transistors
IBM researchers say they've overcome another obstacle in making the nano material graphene a true star in the semiconductor world.
First discovered in 2004, graphene - an atom-thick layer of carbon atoms arranged in a honeycomb lattice - promises the construction of vastly smaller nano electric circuits than even today's tiniest silicon chips. But there are several problems that need to be tackled before it's a practical solution.
One of the headaches in using graphene as a silicon alternative is Hooge's rule — as transistors shrink to ever-smaller dimensions, the tiny electron charges inside a material will threaten to overwhelm a desired signal with unwanted interference.
Scientists at IBM's T.J. Watson Research Center in New York state claim to have found a way to reduce that troublesome electric noise in graphene by a magnitude of ten. And the solution is as simple using as the buddy system.
In their experiments, the researchers found that using a single layer of graphene to build a transistor follows the proportional size-to-interference problem. But stacking another sheet of graphene will greatly counteract the influence of the noise. IBM's team reported their discovery in the trade journal, Nano Letters. An abstract is available here.
Spiky lines coming out of something is bad. Just like in cartoons!
The scientists apparently aren't certain exactly why a double-decker graphene transistor so effectively screens the electric noise, but they reckon it's a step in the right direction. IBM claims further detailed analysis and studies are required to better understand the phenomena.
Cha-ching! Sounds like more funding for the lab coats. Congratulations. ®
COMMENTS
Being a ACS member (and thus having access to the article) - and this being my field....
They have described the difference as being due to the number of state available in the bilayer structure that are not there in the monolayer structure. The basis of conductor -> semiconductor -> insulator is built on the difference in the band structure (energy states) of the various materials. Conductors have electrons in the conduction bands - or there is overlap between conduction and valence bands. At the other extreme is insulators where the band gap is large between the conduction and valence bands. These band structures are set by basic quantum Mechanics. What they have stated is that there are sets of open states in the bilayer material that suppress some of the higher (noise) states available in the monolayer system.
Why
@Faraday cage: Possibly
@UTP: Not. UTP works by twisting the out and return paths closesly together which removes common mode interference. In this case it seems that things are more close to being shileding than an actual UTP.
Not being a physisist (I probably can't even spell that right) here's my guess....
THis could also be some sort of capacitive "electron inertia" effect. If you have two bodies close together then moving one electron causes changes in the field which change the electrons in the other body. This means that it is harder to move an electron that is in such a situation than a free floating electron. If an electron is harder to move then it will be less prone to disruptive noise.
[Mine's the white lab one]
UTP
Unshelded Twisted Pair.
Paris & Britney?
Too hot to wear a coat today...
orders of crap
Never mind all this magnitude stuff, what about these 'transistors'? All they show is a mesh. There's a long way to go before a conductor becomes an active device. How are they doing that?
A couple of things
"Could it be the same principles that make a faraday cage work?"
Perhaps, in the very general sense that Maxwell's equations and charge conductors are involved. Since this is a quantum system only two atoms thick, the detailed explanation is going to end up being a bit different from any classical model. I'm sure they have some ideas, but I haven't seen the original article yet, so I can't comment on that.
And as for "order of magnitude," in physical science, so far as I've ever encountered (being a professional in the field), it invariably means a factor of ten. If it occasionally means something different to computer scientists, then this is a cultural difference that I (and I expect many other scientists) have never encountered.
In practice, when you say "an order of magnitude," you mean "about a factor of 10." It might be 8 or it might be 11, and this is commonly understood among physical scientists. But when you say "a factor of 10" and it's 8, then people could accuse you of dishonesty. So the two phrases don't mean quite the same thing. One is more precise than the other.
