Slashdot Mirror
Progress Toward Single Molecule Transistors
Fungii writes "There is an amazing story over at sciencedaily.com saying two research teams have managed to create single molecule transistors, looks like we don't have to worry about limitations on feature sizes for a while."
still have to worry about quantum effects and electromigration
Two Breakthroughs Achieved in Single-Molecule Transistor Research
Results promise advances in nanoscale electronics
How small can electronic devices get? Nano-small! Two teams of scientists have fashioned transistors from single molecules, and report their results in the June 13 issue of Nature.
The ability to use individual molecules for electronics is a coveted breakthrough for science at the nanometer scale and for electronics industries because of the potential to shrink the size of components well beyond what is possible using conventional lithography techniques.
Transistors, traditionally made from silicon, regulate the transmission of electrons across barriers. The barrier height, and hence the electron flow, can be controlled by applying a small voltage to an electrode that acts as a gate. At the Cornell University Center for Materials Research, funded by the National Science Foundation (NSF), Paul McEuen, Dan Ralph, Hector Abruna and colleagues wedged a molecule containing a single cobalt atom between gold electrodes. They were able, using a gate voltage, to control the transfer of electrons across the cobalt atom, demonstrating the ability to regulate electrical flow at the smallest possible scale.
Hongkun Park and coworkers at Harvard University developed a transistor by inserting a different molecule containing two atoms of the metal vanadium between gold electrodes. The scientists were able to start and stop the flow of electrical current by adjusting the voltage near the bridging molecule, and observed magnetic interactions between electrons in the gold and the vanadium atom.
Park's research was supported by individual NSF grants and by the NSF Center for the Science of Nanoscale Systems and their Device Applications at Harvard. The di-vanadium molecule was developed by NSF grantee Jeffrey Long at the University of California at Berkeley.
By demonstrating the ability to control electron flow across one molecule and even a single atom, scientists have become optimistic about the ability to someday build the smallest possible electronic components. An important aspect of the research is developing the ability to conduct electrical measurements at the nanoscale; for example, to measure the electrical properties of single molecules. Both of the NSF-supported experiments demonstrated this ability.
-NSF-
For information on the materials center at Cornell, see: http://www.ccmr.cornell.edu/
For information on the nanoscience center at Harvard, see: http://www.nsec.harvard.edu/
Someone translate this into plain language for me, perhaps? It sounds like this is some kind of important breakthrough, but what does it actually mean on a practical level?
...Hand soldering SMT's was a bitch!
"They do not preach that their god will rouse them, a little before the Nuts work loose." Kipling, 'The Sons of Martha'
I read the article but couldnt find actual sizes anywhere (bacterias vary widely in size) but i wanted to know how smaller than the current transistors inside CPUs these are.
Anyone know ? (BTW: which proc has the smallest rite now ?)
no text
The molecules involved in making the transistors, metal vanadium, are individually the size of golf balls.
;^)
Ryan Fenton
It took twenty odd years for power suppplies to catch up with the power stability requirements of the Feild Effect Transistor (yes, the lowly FET). It wasn't a viable device (it was rediscovered when it's proof-of-concept fell out of a cabinet) until supplies were rock-stable. I wonder how many years until powersupplys will be stable enough to support these beasts.. Looks like we're going to be looking at pico to nano amp/volt stability requirements.
:)
I wonder what the cooling requirements for a 60 Ghz 0.5 volt cpu is going to be?
Everyone knows bigger is better.. What is with this obsession with making everything small?
This article is refusing to load for some reason, but I've read many articles on molecular computing before. And if this article follows the same strategy that the others did, when the current passes through the molecule, it bends, causing the other current to flow. But to me, this seems as though 'tcould be a hinderence. Think about it this way: you put millions upon millions of these things together to make a processor. But since the all rely on contortion to change state (0 to 1 and vice versa) how would they all stay together without breaking apart? Molecules have a certain amount of play, of course, but if just the right amount switch states at once, bonds could break, or it could make it impossible for other molecules to switch states. Would they be attached to something, and, if so, would the thing they're attached to cause them to not operate at top speed, if at all? Maybe you could use carbon nanotubes to secure them, because they can spring open and closed, but that would add much unneeded complexity at this point, barring even greater advances in self-assembly technology.
We now have confirmed reports from an informed Orange County minister that Ethel is still an active communist.
Remember that there are limitations to how small we can make circuits. If you put two molecular sized tranistors very close to gether, you will have major issues with tunneling.
What next? Two transistors in a single molecule? The article doesn't say how well did that device actually function as a semiconductor, I quess it isn't the point.
In any case, I don't think anyone should go rush buy their stock. Semiconductor fabs are so expensive even evil multinational corporations have to team up to build them. I don't think this technology will compete withing next ten years (tm)
This means very little on a practical level at the moment; it's more an indication of what's possible than anything we're going to see actually used in the next few years (IMHO). It's an ongoing question just how small a transistor can get and still be functional, and this seems to be an answer to that: it can get molecule-sized. Whether a molecule-sized transistor can or will be actually be usefully incorporated in any practical device is another question (well, technically it's two other questions).
At the very least a practical device using transistors that small would have to have a radically different design from present-day circuits, including vastly larger error-checking capabilities and probably some self-repairing abilities. Heat is a problem even now, and in circuits on this scale it wouldn't take much for the circuitry to literally shake itself apart. Quantum effects, which are negligible on today's scale, would introduce all kinds of errors into both the input and output of such small circuits if you tried to simply copy the same structure onto the smaller scale.
Speaking of which, the issue of actually hooking in I/O at such a scale is both a major hurdle for some applications, and a major possibility for practical use in others. For example, this is the kind of scale you'd want if you're going to try to splice more-or-less traditional electronic circuitry directly into fine nerves; when the electronic eyes currently just coming into being become fine-grained enough to support normal vision, they'd probably need extremely fine connections to individual nerve fibres in the retina.
This is a real wowser of a breakthrough, and major kudos rightfully go to both teams. It shows that there's a long way to go before transistor-type circuits can't be made smaller. By the time we actually get that far down the Rabbit Hole it's likely that we'll also have other information-processing techniques available, such as quantum computing (and this technology, once developed, might be just what is needed to usefully access the output of qubit-based systems).
as with most quantum work. it may work well when isolated as with most CERN experimaents but I am sure that decoherance will cause problems. But ti is a fantastic breakthrough and I look forward to seeing how they over come manufacture problems.
Don't worry! Everything is getting nicely out of control....
The physics is such that the theoretical frequency response must be very high. The only problem could be capacitance on the input. I wonder about the gain, also.
As processing power increasse to 10-100 times what it is now, what will the role of software developers become? Will the additional power allow developers to ignore perfomance more and more, and focus on correctness and features? Or, will developers tackle bigger and bigger problems, and therefore require better asymptotic performance of their algorithms? I don't think computer science will ever die, but it's something to think about.
I don't think the diVanadium transistor works at room temperature.
The first molecular transistor working at room temperature was based on an individual semiconducting carbon nanotube, by Tans, Verschueren and Dekker in Delft, the Netherlands. It was published in Nature in 1998.
Tans et al, Nature 393, 49 (1998)
Further, Tour and his group have synthesized molecular transistors (he calls them "Moleisters") about a year and a half ago.
"Moleisters"?? What awful nomenclature, sounds scandalous. How about switching it around, call them "Transeculars." Hmm, that's not much better... But hey, it's all good, whatever helps them sustain an electron.
Weeks of coding saves hours of planning.
who cares if you cant actually use the damn thing
.13 or .9
mask costs are about $2million for
so its not the same and relatively few people can afford it
unless you share and then you can only really get engineering samples
AMD made the smart move of UMC and TSMC are just ARM/MIPS prod lines with some custom phillips stuff
IBM, Intel and maybe TI are the only people who can aford to do this anymore....
if you wanted me to put money on it I would bet IBM and the rest wither (yes Intel will outsource eventually)
regards
john jones
This should really be a boon for portable devices, as smaller sizes are always benificial to them.
/. speling.
+1: stating the obvious.
Incidentally, portable devices are also an area that Linux truly shines.
+1: Linux rules.
I would wager that the first OS you will see running on them is Linux.
+1: Linux rules.
they will begin to leave propritary embeded Windows OSes [...] for the much more dynamic Linux.
+1: Linux is better than Windows
oh, and of course the standard +2:
I think you can store at least 6 or 7 pieces of information into an atom. Surely you could stash some stuff into a proton or quark or something. Maybe you could use Microsoft's disk compression technology for atoms. Microsoft Atom Doubler.
Exactly what I was going for (except the spelling, at which I am naturally bad).
- Avoid conflating nanotech with chemistry.
- Avoid conflating nanotech with biology.
- Describe economical fabrication techniques that are not far more advanced than the nanotech being described.
We can be thankful that the referenced article succeeds on the first 2 counts. Unfortunately and quite preditably, it fails on the third count.Seastead this.
This is indeed grand news but there are many obstacles between developing a single molecule transistor and building microprocessors out of same. The difficulty with integrated devices is not whether or not a transistor of a given size will switch, but making the lithographic process of printing the things on the die accurate enough that they can be made that size in the first place. Also last time I looked the transistors on a microprocessor were not suspended between gold electrodes.
Noise may be another issue, since now we must be talking about handfulls of electrons so that a small number of rogue noisy electrons could push the signal across the noise margin and flip the logic.
Alternatively with that size of device we could be designing with high redundancy rather than relying on accuracy - a whole new design paradigm could open up.
Nemo me impune lacessit
Will the additional power allow developers to ignore perfomance more and more, and focus on correctness and features?
They already ignore performance and focus on (unneeded) features. Now there's only correctness to go.
...the power stability requirements of the Feild Effect Transistor...
FETs can be operated under a much wider voltage range than junction transistors.
In logic ICs, my "TTL Data Book" (Texas Instruments, 1976) the voltage requirement for bipolar chips is 4.5 to 5.5 volts for the 54 (military) family and 4.75 to 5.25 volts for the 74 family. On the other hand, for FETs, I have the 1976 "RCA Integrated Circuits" handbook, which mentions a 3 to 12 volts operating range for most of the chips in the 4000 family.
As for discrete devices in analog circuits, FETS and bipolar transistors are more or less equivalent in power supply needs, except that FETs behave as variable resistors in very low drain-top-source voltage ranges, so they are sometimes operated in close to zero or negative voltages, while bipolar transistors need at least 0.5 volts collector-to-emmitter to operate linearly.
Some programmable logic technologies handle wiring with a uniform sea of logic gates connected by fuses, and you create a particular logic circuit by selectively blowing fuses. The HP/UCLA rotaxane work involves essentially the same idea, using molecular switches at the intersections of a 2D grid of molecular wires. In addition to some discussion here on Slashdot, there is more at Nanodot, and a fairly extended discussion on sci.nanotech.
Solving the problem of routing specific wires to specific gates, and doing it in a way that's reliably manufacturable in mole quantities, will pretty much relegate today's foundries to niche markets. But that's probably a long way off, numerous problems to solve to get there. Interesting times ahead.
WWJD for a Klondike Bar?
Summing it up with a roleplay...
Rich Man: "Damn my computer just broke!"
Passer By: "Whats up with it?"
Rich Man: "Well with the heat of my hand on it dang thing browned out"
Passer By: "Oh... weird... well open it up and I'll have a look"
Rich Man hands it over
Passer By: "Next time get a brand name wristwatch"
Rich Man: "No, no thats my palm top"
Passer By slips it down sleeve...
0xC3
There was an interesting paper illustrating a nand gate using carbon nanotubes. You need circuits as well as devices. Their carbon tube has the 'amplification too'
Well, the Feild Effect Transistor may have that problem but 30 years ago Field Effect Transistors were being used to replace vacuum tubes. It was basically a tube bottom with the same pin layout as the tube and the FET with appropriate voltage dropping resistors. As a direct plug in replacement they had to work with the same power supply as had been the tube being replaced.
I see even classic Slashdot is now pretty much unusable on dial up anymore.
Inventor of holograrphic storage for years has been publishing patented concepts on molecular applications and technics, this looks interesting, * Photon Induced Electric Field Poling Theory Invented by Michael E. Thomas using Patented Integrated Semiconductor R/W Head concept has many other uses 2D/3D Optical Storage 2D/3D Optical Disk VCR 2D/3D Optical Disk/Card Digital Photography 2D/3D Xerography 2D/3D Optical Wiring 2D/3D Optical Integrated Circuits 2D/3D Photonic/Molecular/Atomic Switches for Broadband Telecommunications Holographic Storage for the Film Industry and other Copyrighted sources for Absolute Protection from IT Theft * Patents Granted
A list of few corrolaries (sp?) from the experiment:
1) computers will be less stable: literally. quantum tunneling will eventually screw up enough of your circuit to a point of "beyond repair", really soon, even if there are error checking / repairing enabled -- i still havn't seen any self-repairing technology where the chip would be able to insert one valladium (whatever) between two pieces of gold electrodes. today's large quantities of error checking are designed to correct only a few predictable errors -- i don't even think there are any self repair functionalities on logic chips; (memory chips have redundant rows / columns, but this would be REALLY hard to implement on a logic chip -- and if it was done it will cost TONS of area, which besets (?) the benefit from the small size. computers based on molecular technology will probabbly have this "half life" -- within 5 years half of all chip made will fail despite all the error checking -- so you are absolutely required to buy chips -- and it is also likely that a chip will simply become broken from sitting on a shelf (quantum tunneling, etc). ha... that will be the day =)
2) voltage levels -- not really a problem but somewhat interesting -- small transistors operate on small voltages -- crosstalk and other interference / PS noise, etc will totally screw up your chip, real fast. (differentical signals will help) You will need tons of amplifiers to actually be able to tranmit the signals from this low, low voltage chip to the other components.
3) heat -- wow this sucker packed this tight will be a furnace!! probabbly reaches melt-down voltage within no time... this is already a problem in today's chips -- imagine how bad it will get with small transistors like that (smaller chip, highly defined, descrete areas) -- thermal expansion locally (part of the chip doing stuff) will put stress on the rest of the chip -- and if the heat itself does not pop a transistor / molecule out of place via quantum tunneling / molecular vibrations, the physical stress sure will. this will be interesting to see how they figure it out.
4) not so related: just because someboy comes up with some technology does not mean it's production ready or shows how far the transistor can be pushed! moore's law, as it stands today, still have a realistic barrier couple years down the line, and single transistors does not make it into a viable industrial process -- it took a LONG time for them to figure out the details of today's photolithography -- the masks and CMP (chemical mechanical polishing) took them a LONG time to figure out.
My life in the land of the rising sun.
Not to discredit the scientific work of the people here, but about a year ago another group for Eindhoven (Netherlands) also made a single electron transistor (SET).
They used a pair of tweezers from an atomic force microscope to make dent in a carbon nanotube.
Details can be found here at Science 2001 July 6; 293: 76-79; also online but requires a subsicription.
I think that the switching of a transistor by one electron, is more important that a transistor made with a single molecule. In the article it is never stated how many electrons are needed to swict the on and off state of the transistor. The size in neither mentioned, they speak about clusters and a single molecule but a single molecule could be qiute large....
So the carbon nanotube used by Postma et al could even be smaller and uses only one electron.
This has been in development for a long time, and quantum theory holds that it is possible, however impractical. The problem that will occur is the fact that maintaining superposition is damn near impossible. Temperature, magnetic fields, etc. can very easily cause an electron to flip rotation, such that the 1/2 spin and internal backspin will easily slip into one of two states. The fact that decoherence is so common means that you very well could have a single-atom transistor, but there would have to be extreme controls around each such transistor so that the valence shell of any one transistor doesn't inadvertently tamper with its neighbors. Even besides that, you may very well have to keep your monitor halfway across the room to keep from b0rking your processor. It's neat, in theory, but still at least 10 years down the pipe from being near practical in even a scientific or academic setting.
Never attribute to Hanlon that which can be adequately attributed to Heinlein.
... yeah, but I bet Radio Shack will still sell them 2 to a pack for $2.99.
--- Jason Olshefsky
Karma: Poser (mostly affected by adding this line long after everyone else did)
I wouldn't expect to see any circuitry built directly from these technologies - though I could be wrong. But what it does say is that there is no absolute theoretical limit above the size of a single atom at which transistor operation is no longer possible. We will continue to progress along the lines we are already travelling - finer and finer masks, more sophisticated optical processing, probably electron beam writing, or maybe direct electron masking. But we now know that there is no quantum bogey man going to jump out and say that it is no use shrinking feature sizes any more because transistors just don't work at that size.
This contrasts with hard-disk technology, where there is almost certainly a minimum size to a magnetic domain (though it may be smaller than we now thing - see the latest "pixie dust" enhancements which shrink the stable size of a domain). Somebody who works for a disk-drive manufacturer told me that their R&D people reckoned that they would be hitting brick walls erected by the laws of physics about 2012. Contrast seciconductors, where on one side a senior honcho at TSMC was reported as saying thet he could see the engineering advances continuing to at least 2020, while these results says that the physics carries on even further.
Well before we get to the single atom transistor or the single atom memory, we are going to have problems wiring such chips. I cannot see such high densities being achieved with the wiring for true random access. I think either the wiring density will mean that larger (and hence easier) cells will fit under the wiring, or that some kind of shift-register type scheme will have to be used, slowing random access time.
Which in reflects on computer architectures - we could be adding even more levels to the current hierarchy of register - L1 cache - L2 cache - main memory - disk. Could we usefully used a few Gbyte of (volatile) ram disk on a chip? Say, transfer speeds the same as current disks (100 Mbyte/sec, compared to the 1Gbyte/sec of PCI-X and several Gbyte/sec of main memory) but zero rotational and seek latency?
Consciousness is an illusion caused by an excess of self consciousness.
Ok this is really just a theoretical (and bad) idea.
Maybe there would be some way to control quantum tunneling where one transistor 'tunnels' to a different one for true and a different one for false. Theoretically it would cut down on heat issues, and up speed in the processing.
I know that there are know hints as to go about this as of yet, but it was just a thought.