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Graphene May be the New Silicon
esocid writes to share that University of Maryland physicists have demonstrated that the material of the future may be graphene rather than silicon. Electricity conduction through graphene is about 100 times greater than that of silicon and could offer many improvements to things like computer chips and biochemical sensors. "Graphene, a single-atom-thick sheet of graphite, is a new material which combines aspects of semiconductors and metals. [...] A team of researchers led by physics professor Michael S. Fuhrer of the university's Center for Nanophysics and Advanced Materials, and the Maryland NanoCenter said the findings are the first measurement of the effect of thermal vibrations on the conduction of electrons in graphene, and show that thermal vibrations have an extraordinarily small effect on the electrons in graphene."
...refers to electron mobility, a concept I hadn't previously encountered. But it's easy enough to understand: if I apply a unit electric field to a material, how fast does it make the electrons drift? This is the mobility.
Apparently graphene (also new to me ... a single-atom layer of carbon) is exciting because it has much higher electron mobility than silicon. Which leads to faster switching times, although they don't explain that part.
All this seems to be theoretical at the moment, due to insufficiently pure graphene. Still, 100th the switching delay is not a bad target to be aiming at... 100Ghz processing!
He must get "Herr Fuhrer" jokes all fricking day
I, for one, welcome our new carbon based overlords :-)
Seriously, however, I don't expect to see a CPU based on this anytime soon.
Ian Ameline
Oh yeah well thats nothing compared to copper wire!
So, when do I get my 360 GHz sixteen core processor?
I recall that early compact discs had this problem, in which oxygen trapped in the plastic would oxidize the aluminum and reduce its reflectivity.
Request your free CD of my piano music.
I recall hearing some people making noise a few years ago about the possibility of using synthetic diamond as a replacement for silicon. What happened? Did the technology not work as predicted, or is graphene a superior material?
I don't think graphene is a new material. It forms the basis of nanotubes, which have been studied for over a decade.
...In graphene the intrinsic limit to the mobility, a measure of how well a material conducts electricity, is higher than any other known material at room temperature. But how does it do at, say, 70C?
Web comic strips are about as funny as blog "journalism" is credible.
Maybe it makes a great negligee?
I know, I know, a different enhancement problem set from the target of silicone enhancements. But I prefer the more natural sort of enhancement, myself.
But the health issues of silicone and asbestos and the like do raise a question to me about graphene and other carbon filament materials.
...on Graphene Valley
it might feel like a young bespectacled chap... it might feel like you! who knows?
One PITA in MMICs is the lossy substrate. More conductive = eddy currents = losses.
Thanks for answering :)
I don't think f8d beats xkcd at being xkcd ... that would be silly. xkcd wins at being xkcd, and is one of my favourite webcomics.
So really the comparison is kinda pointless. But it's noticable, and so makes a good sig :)
Yeah, like you know how real breasts feel.
Dis will be gut für das Kübelwagen MKIII! Ze Material is only one Atom zin!
Err... Bah Weep Granah Weep Ninni Bong?
1) Do you have a decent quality oxide for it?
2) Can you make good low resistance contacts?
3) Can it be doped?
Graphene probably fails 1 and 2 at this point. I'm not sure about 3.
2D (graphene) and 1D (carbon nanotube) semiconductor systems have a lot of trouble with surface effects ruining your ability to make decent devices.
Silicon Valley has a way better ring to it.
Take pride in what they can do with their graphene calculator?
sorry.. no use unless it can be used for breast implants
Will I have to borrow a semi-conductor every class now ?
What if someone chews on mine ?
"how that thermal vibrations have an extraordinarily small effect on the electrons in graphene" does this mean that graphene transitors will have HFE as a stable paremeter?!? that would be seriously awsome!
4) Can it be etched easily to form structures?
Did anyone else read the title as "Gangrene May be the New Silicon"?
Yes, using conventional e-beam lithography.
Here's the press release with a link to the paper.
http://www.thinkgene.com/um-physicists-show-electrons-can-travel-over-100-times-faster-in-graphene-than-in-silicon/
Yes, you can etch away all kinds of carbon with hydrogen plasma easily.
There is a spark in every single flame bait point.
Yes. the linked article shows photomicrographs of quantum dots made on graphene surface that are set up via doping and can act as gates. I'm going to guess that perhaps a resistive base will be used, photolithographed, and via some magic process the graphene "wires" will be deposited onto the base into the channels or, perhaps pressed onto the ridges, before being doped further.
Graphene has some of the same problems as carbon nanotubes, so while doing basic electrical characterizations of this material are major news right now (that shows you how new this material is), ultimately using this material and convincing the 4 or 5 companies with the capital to have state-of-the-art fab facilities to switch over from silicon-based CMOS technology is looking way, way, WAY into the future.
... a Yagi antenna resonant at a wavelength somewhere between 700nm and 400nm. Now I just need a high power transmitter and some feedline to connect to it.
now we need to go OSS in diesel cars
Just like sand bags.
footprints.
my Tin Foil hat with Graphean gray hair remover. (Graphite is grey to black right?)
Chemistry 101:
Silica : crystalline silicon dioxide aka sand
Silicon : element # 14, greyish semimetallic crystalline
Silicone : Inorg. polymer typ. -Si(CH3)2-O- Liquid or can be rubber if crosslinked. Using for boob jobs.
Chemists are going to be pissed to hear this! New periodic tables, new reactions, new names for all sorts of all sorts of chemicals. And where is the Silicon going to go? Also -- what are the geologists going to think? Over 25% of the earth's crust is made of the stuff!
If I had mod points, you would so get them all for that. Best reference ever.
The role of the writer is not to say what we can all say, but what we are unable to say. -Anais Nin
Sieg Hail Michael S. Fuhrer!
1. I suppose if they are using hafnium oxide, then an MBE system might be able to deposit a similar compound onto graphene.
2. Good question. If the answer to number #3 is that you can't dope, then you're probably screwed.
3. Doping might be possible as with SI using the III-IV elements.
4. What about the mobility of the holes? Or would this end up being a specialty player like GaAs in the high frequency range where the intrinsic electron mobility is pretty damn good (8500 cm^2/V-s) but the Hole mobility is down right terrible? (400 cm^2/V-s).
If the hole mobility is absolutely poor compared to the electron, it might never find a home in mass produced electronics like silicon is. But then again, if it's an order of magnitude better than that of Si, and can be economically and reliably produced then I imagine we'll see this first in mixers/modulators/clock gens/detectors/anything else that needs speed. Eventually it might trickle down to unseat the king of ICs, the almighty silicon.
Graphene is certainly a lot like carbon nanotubes, but is much easier to work with. Where you have to hope to get a semiconducting crystal structure in a nanotube (or make crappy transistors based on defects), you can pattern graphene to make a transistor. Which directions you cut the 2D sheet determine whether it is metallic or semiconducting. There are some problems with this, and practically speaking any small channel (10 nm, I think) of graphene is semiconducting. Fuhrer has shown (along with other people) that graphene can make pretty good transistors (very fast switching, thermally stable and I'm sure I'm missing some stuff).
It can be doped. This is another thing Fuhrer has done (as well as other people... but this is his article we're talking about). You don't want to insert something into the crystal structure (that ruins it), but you can layer the top of it with potassium ions (about 1 per 1000 carbons), which dopes it just fine. This isn't a bulk semiconductor though, and the addition of charged impurities (dopants) decreases device performance (in bulk, it's a metal). You can very easily electrostatically gate graphene in any direction you want; transistors and PN junctions are easy to make this way.
It is not hard to make graphene. The "scotch tape" method from Manchester is widely used, but there are a number of other ways to do it which may be commercially viable: oxidizing graphite, ultrasounding graphite with special polymers (Dai's method), growing it from SiC wafers. Of course, none of these really work yet, and may never be economical.
Graphene is stable in air (almost all devices are measured in air at some point), and liquids. It's not going to spontaneously dissolve on you just because it's only 1 atomic layer thick. It's actually very robust.
It can be used with silicon processing techniques. People are using SiO2, HfO2 and all the usual silicon processing with it.
Big companies are looking at this material. IBM has already reported results on their work at physics conferences, I'm fairly sure that the more secretive companies (Intel) are also working with graphene... just like they worked with nanotubes.
5. Does it have 30 years of technology refinement behind it?
If electron mobility was important silicon would have been replaced by Galium Arsenide years if not decades ago. GaAs can pass all of the first 3 requirements suggested by the parent - but not in a scalable way. For example you can get a good quality insulator on it, but its just bloody hard to do.
In theory, there's no difference between theory and practice; in practice there is.
Because graphene has no gap, by simply gating and controlling the gate voltage you can induce charge carrier, which is essentially the same as dopping in a usual gapful semiconductor.
The only possible interpretation of any research whatever in the 'social sciences' is: some do, some don't
As I understand it, a "hole" is just the absence of an electron, which leads to a net positive charge for a particular atom. Kind of like a positive ion, but I think use of the term "ion" is limited to liquid solutions/gases/plasmas.
An electron can move and fill a hole, but leaves another hole behind in the location it just departed. So a "hole" moving in one direction is entirely equivalent to an electron moving in the opposite direction, is it not?
If so, why does this term have any usefulness, if, instead of saying "the hole moved from point A to point B" you could just as easily say "the electron moved from point B to point A"?
Help me understand why much ado is made about holes.
That that is is that that that that is not is not.
Will a 100Ghz processor play Crysis?
Man, how old are you? 40? :P
Rampant carbon sequestration destroyed the Dinosaurs' tropical paradise. I'm here to help repair the damage.
A friend of mine works for Prof Andre Geim in the Mesoscopic Physics Group at University Manchester and was one of the people to first prepare graphene crystals. They have a spin off that is selling graphene flakes to some interested industry altho the demand is not huge at the moment. If you want to play with graphene flakes of your own you can check them out here.
It is interesting stuff - I saw Prof Geim speak about it and it seems to me one of these areas where quantum theory and experiment intersect, such as with Bose-Einstein Condensates. It's not really my field but the preparation of them is interesting. M
M.
I didn't read the article (this is /. after all), but if it's made of graphite spread really thin (one atom thick), isn't it still just graphite? Just really thin? It sounds more like they discovered special properties in application of the material, as opposed to what it does when sitting in my pencil.
I will shred my adversaries. Pull their eyes out just enough to turn them towards their mewing, mutilated faces. Illyria
"When information is power, privacy is freedom" - Jah-Wren Ryel
They are MANY materials with superior electronic characteristics to silicon. the original transistor industry used gallium, arsenic, and indium. However nothing comes close to a billion devices on chip for $100.
That's the first time that's ever made sense to me. That's gottah count for something.
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So when the computer breaks down you can still use it like a pencil to finish your work.