First Graphene Transistor

An anonymous reader writes "UK researchers are announcing the first ever workable transistor made of graphene — that's one layer of carbon atoms. It's thinner and smaller than a silicon transistor can ever be, and it works at room temperature. When silicon electronics are dead, this is what many speculate is going to take over. There's slight controversy as they decided to announce their results via a review article, rather than wait for their (submitted) peer review paper to come out."

Comments

That's one slick transistor

[Anonymous Coward]

Thank you and goodnight! :)

Works at room temperature?

[timeOday]

Wow, silicon will never match that! Now I don't have to work in this darn freon chamber all day.

Re:Works at room temperature?

[wass]

You know of a silicon single electron transistor that also works at room temperature? I know some groups have made room-temperature quantum dots previously, but I don't know of any silicon ones. Those other room-temp ones are carbon nanotubes with nano-leads spaced about 10nm apart, in which case they're really graphene already.

Anyway, graphene has a number of very interesting properties, such as its band structure which looks like a Minkowski space-time cone (or MCP from Tron). Graphene is such that its Fermi energy lies exactly at the cone intersection, and is a so-called zero bandgap semiconductor. Density of states around these conical regimes open up all sorts of applications.

Interesting story, one group in physics spent lots of time and $$$ trying to make a nano-pencil to try to create a single graphene layer. Ie, they put a chunk of graphite on an AFM tip, and tapped it onto a substrate, making the world's smallest pencil, and thought they may have had a few areas where the resulting line was single layer thick.

In one of the ultimate cases of getting scooped, a competing team from Harvard took a pencil, scribbled on a piece of paper, and used scotch tape to tap down on the pencil marks. Then tapping that tape onto another substrate gave large areas which had single graphene layers. So the first group was scooped by a team that used literally pennies worth of materials on a process that takes only minutes, while they spent over a year and tens of thousands of dollars on the nano-pencil technique! Cue cliches about thinking outside the box.

Re:Works at room temperature?

[eMbry00s]

Scotch Tape + Pencil = Über-transistor. Mac Guyver would be proud.

controversy

[esocid]

I don't really see it as that controversial. If their research doesn't hold up under peer-review it's their loss, although I am very surprised that Nature is publishing this without it being reviewed. Let's hope it doesn't turn out to be a clone (pardon the pun) of what happened in the faked S. Korean cloning research.

practical?

[wizardforce]

graphene transistors need to be able to be mass-produced, scalable and just as reliable as alternatives [silicon, quantum computers etc.] most importantly, relatively easy to make- [why diamonds though semiconductive are by no means replacing silicon] it will be interesting to see how this competes in the future though.

Re:practical?

[Chris Burke]

Yep, those are all realistic concerns and issues that must be addressed before this will really become a silicon killer.

At the same time, look at the amazing technology that goes into producing silicon chips today. Something that seems ludicrous to mass produce today may just take a decade or so of process and manufacturing technology advancements. On the other hand more research will also probably give silicon a longer life than what anyone predicts (since the death of the silicon CMOSFET has been predicted for decades).

So I agree, what comes in the future will be interesting.

Re:practical?

[Rosco P. Coltrane]

need to be able to be mass-produced, scalable and just as reliable as alternatives [silicon, quantum computers etc.]

John Connor, is that you? I gotta tell you, when you come from, quantum computers might be mass-produced, scalable and reliable, but today they aren't just yet...

Re:practical?

[cyfer2000]

There are two ways to make graphene I have known, one is to exfoliate graphite and the second one is to produce an oversaturated silicon carbide single crystal, and the graphene will grow epitaxially from the carbon layer on the surface of the silicon carbide crystal. None of these two can be "practical" IMHO. I also believe the researchers claim the new transistor is "practical" just to differentiate them from the old ones. Anyway I will read the real paper on Nature Materials and see what Novoselov's group has done this time.

Re:practical?

[MindKata]

I really hope the technology works but I have doubts about its reliability outside the lab.

Its one thing getting one transistor working in ideal conditions ... its another to build a circuit with at least a billion of these transistors (which it will need, if it is to compete with Silicon for Computer parts). Although that said, as these transistors will be so fast, there could be more practical high frequency analogue applications.

I think background radiation will be one of its main reasons it will fail for a CPU and RAM. With a structure 1 atom thick there is no room for failure. Either an atom exists or it doesn't. Knock an atom out of place then it fails. With a conventional transistor as its bulk material all that happens is it degrades its performance but it can take it (most of the time).

When I first started to read the article I thought it sounded a bit like the Ballistic transistor. Its interesting the Wiki also mentions Graphene as a way to form Ballistic transistors. http://en.wikipedia.org/wiki/Ballistic_transistor

I really hope it works as it could create incredible computers ... But even analogue applications could be very interesting (like maybe even operating in the Terra Hz range :)

Re:practical?

[dimeglio]

I think background radiation will be one of its main reasons it will fail for a CPU and RAM. With a structure 1 atom thick there is no room for failure. Either an atom exists or it doesn't. Knock an atom out of place then it fails. With a conventional transistor as its bulk material all that happens is it degrades its performance but it can take it (most of the time).

Think how much redundancy you can build into devices of that size. You can have thousands of quantum based CPU's each of them redundant and part of an array for less than the size of current devices. Decisions could be consensus based thus eliminating rogue CPUs for example.

Re:practical?

[crgrace]

That's true, and actually with current silicon device sizes a single alpha particle strike has the possibility of flipping a bit in an SRAM. This is one part of why NASA uses old cpus -- one of the simplest methods of radiation hardening is to simply use larger structures that require a larger amount of energy to change state. Then they add more shielding and such on top of course.

That's actually not true at all. The chance a transient error (SRAM bit flip) or worse, a long term change in the threshold voltage of a device actually gets worse when the structures are larger. That is because the chance for a radiation event to occur in the gate oxide is linearly proportional to the thickness of the oxide. Fine-line CMOS has thinner oxides, so it is more tolerant.

On top of that, what you are discussing (shielding, structure geometry) is called radiation tolerance, not radiation hardening. A radiation hard IC process implies dielectric isolation between the devices. For example, the use of SOI is quite prevelent in nuclear/space applications. The reason NASA uses old CPUs is because they are available in rad-hard dielectrially isolated technology. Intersil in Palm Bay, FL, still has rad-hard 286s coming off the line right now. Dielectrically isolated IC processes with the feature sizes needed to produce modern CPUs simply do not exist because of the lack of an economic incentive. That is the only reason NASA and DOD use such old CPUs.

FINALLY...

[Penguinshit]

A use for Folgers.

oh, wait; GRAPHene... oops.

Re:2020 is a long time

[julesh]

                          Current industry predictions suggest that by 2020 silicon devices will have shrunk to about 20 nanometres... ...after this ... graphene will come into their own. And that gives scientists time to perfect the tricky fabrication methods...

I think if this is to be used in consumer products, market forces will tell them how long they have. Big leaps often come in short time spans. 13 years is a long time and it seems the longer we wait for something to come to market, the more likely it seems to be vapour ware. If this is pure research, they can take their time (and pure research is a good thing too).

I suspect, in fact, they're being hopelessly optmistic thinking they have 13 years until silicon transisters hit 20nm feature size. The last 5 years have seen 130->90->65. We're already in the gear-up to 45. Next 5 or 6 years, by this trend (which shows only one sign of slowing -- exponentially increasing costs) we should see 45->32->22. And given that apparently most transistors in 65nm chips are actually smaller than 65nm, that's probably the predicted "20nm limit". If there really is such a thing.

Re:What's with the picture in TFA?

[PhysicsPhil]

I mean, the article's about a completely flat sheet of atoms joined in a structure with four edges from eac node. So, why are they showing a ripply surface made from a hexagonal structure, with three edges from each node?

As you note in your follow-up post, the hexagonal bonding structure is correct for graphene. The rippling motion is a result of thermal fluctuations. Normally you don't see it much because the graphene is bonded to a substrate, but as the second link in the main article explains, free standing membranes do actually ripple.

Re:Make it first

[ozmanjusri]

whenever you use a pencil

Like the GP said; "Good on paper."

Re:2020 is a long time

[Bender_]

The node is supposed to be the 22nm node and is only two shrinks away. This means the big companies are hiring R&D personal for that node right now, we are not talking about 2020.

I would not be worried about physics, but rather about economics. Currently many big companies are exiting process development and cutting edge manufacturing and start to rely on foundries. And we are talking top10 companies: Texas Instruments (inventor of the IC!), Sony, Infineon, Cypress, NXP (Philips), NEC (to some extend). The number of foundries supplying the most advanced manufacturing processes is much less than the number of companies quitting development - maybe 3 to 4.

Less parallelism in development means that there is less variety, which will lead to a slowdown. Also the funding for R&D at tool vendors will reduce as a direct consequence of having fewer people buying experimental tools. By the time the graphene transistor would be ready there may very well be just one or two companies being able to make use of it..

Re:overlord

[Experiment 626]

I think what you meant to say was "I for one welcome our new carbon transistor overloards". I don't know what makes you dumber, the fact that you tried recycling that tired joke or that you couldn't even get the simple equation for the joke right.

In Soviet Russia, tired joke recycles YOU!

Re:overlord

[Aussie Osbourne]

I think what you meant to say was "I for one welcome our new carbon transistor overloards".

In Soviet Russia words misspell YOU!

Re:A cure to global warming?

[jbengt]

I got one.

Plant a tree.

Manufactured controversy.

[Kadin2048]

I agree. I don't understand what's so controversial about releasing a paper via multiple routes. The onus would be on the researchers; if they release via a peer-reviewed journal, while also publishing some other way, and then it's rejected during the peer review, well, they'd look pretty stupid then, no?

That's not very "controversial." It's ballsy, and arguably arrogant and stupid, but I don't think there's anything particularly wrong with it. Personally, I'd like to see more science be published outside expensive peer-reviewed journals, where regular folks can have access to it without going through complicated databases. At the same time, I understand the purpose that peer-review serves, and we don't want to eliminate that along the way.

I'm particularly galled by journals that demand exclusivity agreements in order to accept papers for publication, or have gag rules that quash discussion of papers that are being reviewed. That seems contrary to the collaborative nature of science and generally counterproductive (as well as just generally creepy and fascist; I don't much like the idea of anyone telling me that I can't talk about stuff, particularly if I were someone who'd just spend years working on it).

The only thing I think is a little controversial -- and I'm not even sure I'd choose that word, maybe just "inadvisable" -- is that Nature seems to be going ahead and running the non-reviewed version, even though they could just wait and see a little longer, and make sure that it doesn't get rejected. If a flaw is discovered during the peer review, now it's not just the researchers that are going to look dumb, but anyone who printed the un-reviewed version.

To say that there's "controversy" about the way they released the article seems to imply that there's tension between peer-reviewed and standard modes of publication, and I think that tension is mostly manufactured or artificial. There's no reason why both modes of publication can't co-exist and compliment each other.