Forgot your password?
typodupeerror
Science Hardware

Replacing Copper With Pencil Graphite 122

Posted by kdawson
from the carbon-all-the-way-down dept.
Late-Eight writes "A key discovery at Rensselaer Polytechnic Institute could help advance the role of graphene as a possible heir to copper and silicon in nanoelectronics. Researchers believe graphene's extremely efficient conductive properties can be exploited for use in nanoelectronics. Graphene, a one-atom-thick sheet of carbon, eluded scientists for years but was finally made in the laboratory in 2004 with the help of everyday, store-bought transparent tape. The current research, which shows a way to control the conductivity of graphene, is an important first step towards mass producing metallic graphene that could one day replace copper as the primary interconnect material on nearly all computer chips." Researchers are now hot to pursue graphene for this purpose over the previous favorite candidate, buckytubes (which are just rolled-up graphene). Farther down the road, semiconducting graphene might take over from silicon at the heart of logic chips.
This discussion has been archived. No new comments can be posted.

Replacing Copper With Pencil Graphite

Comments Filter:
  • by HTH NE1 (675604) on Tuesday July 24, 2007 @07:31PM (#19977229)
    This will work just fine until someone decides to clean the conductors at their card's edge with an eraser.
  • by John Sokol (109591) on Tuesday July 24, 2007 @07:32PM (#19977243) Homepage Journal
    Buckytubes (which are just rolled-up graphene) are also known as Nanotubes, have conductivities of almost 1000 WKM (watts per meter kelvin) Graphene sheets should also have similar conductivities. I expect it would also be quite strong under tension.

    This will allow for much more efficient cooling of electronics, even more then Silicon on Diamond technology that is just starting to come out.

    • by John Sokol (109591) on Tuesday July 24, 2007 @07:42PM (#19977379) Homepage Journal
      Sorry, ( I mean thermal conductivities) watt per square meter kelvin[W/(mK)] I use WMK
      To put this into perspective Steel is around 60 WMK, Silicon 149 WMK , Aluminum is 200 WKM, Copper is 400 WMK

      And some nanotubes where reported as almost 10,000 WMK

      Somehow I thought Silicon was more like 60wmk but is higher according to http://en.wikipedia.org/wiki/Silicon [wikipedia.org]
    • Re: (Score:1, Informative)

      by Anonymous Coward
      Nanotubes are different from rolled up graphene. Nanotubes are like straws, generally cylindrical. Rolled up graphene usually refers to a fruit-roll-up type of structure where it isn't a contiguous cylinder.
  • Way back when.... (Score:5, Interesting)

    by Jhon (241832) * on Tuesday July 24, 2007 @07:35PM (#19977293) Homepage Journal
    I had an atari 800 xl years ago (circa 1980s). A friend had spilled milk on the keyboard and a number of keys stopped responding.

    My 'solution' involved opening up the keyboard and retracing the mylar sheet connections with a pencil. It worked great -- but I needed to crack it open every few weeks and retrace it.

    It's amazing what you can accomplish when you are fairly clever and poor.
    • Wow, how old were you? That's pretty innovative. I would never have thought penicl leads make good conductors. OFF TOPIC, but how many of you tried to convince your peers that pencil lead wasn't really made of lead but rather graphite (and therefor not poisonous)?
      • by saskboy (600063)
        I didn't realize that until after grade 6 some time, since I remember thinking a boy with a pencil stabbed hand was going to get some lead poisoning. I'd wager that a question like that on Who can outsmart a Fifth Grader type show, would yield nearly 50% who don't know what the material in pencils really is.
        • by stevey (64018)

          I got stabbed in the arm with a pencil by my "best friend" when I was around 11 years old.

          Even now aged 31 I have a small scar, with what looks like a tiny blue circle around it under the skin of my arm.

          I'll happily claim it is my first tattoo! At the time I wasn't terribly worried about lead poisoning, but it is kinda neat how it has survived pretty unchanged over the years. I'd post a picture online, but it doesn't look terribly obvious unless you really look for it.

          • by JDevers (83155)
            Same here, but mine isn't a circle it is a tiny 0.5 mm dot in the center of the scar on my left palm.
          • by Neoprofin (871029)
            Mine looks more like freckle or birthmark on my palm.

            Nerds need to stop getting stabbed with pencils.
            • by HTH NE1 (675604)

              Nerds need to stop getting stabbed with pencils.
              Shh, don't tell the authorities that. We don't need the nanny state banning normal pencils from schools lest they be used as shivs, spending taxpayer money on special bendable pencils [google.com]. (Someone who knows how those work should update the wiki [wikipedia.org].)
        • by Ctrl-Z (28806)
          Unless you are just slow, it doesn't sound like the average fifth grader would know that either. Hardly fodder for a show about outsmarting fifth graders.
        • by dintech (998802)
          I think todays kids are even dumber. Some even think fries (chips) are made from apples:

          http://www.raisingkids.co.uk/todaysnews/news_07110 5_01.asp [raisingkids.co.uk]
      • Re: (Score:3, Interesting)

        by LionKimbro (200000)
        Not to spoil the awe, but:

        I knew that, and I wasn't brilliant. I think I learned it from my old 200-in-1 kit manual, or early lessons in "how to use your ohmmeter." I remember being instructed to draw a line with pencil, and then connect the ends at different lengths across the line. It recommended striping the line multiple times, as well, and to check the difference.
    • by evanbd (210358)

      Engineering is the art of making what you want out of what you have.

      The best engineering solutions come not from large budgets, but small ones.

    • Re:Way back when.... (Score:4, Informative)

      by LiquidCoooled (634315) on Tuesday July 24, 2007 @08:07PM (#19977635) Homepage Journal
      The Pencil trick is also useful for reconnecting the bridges on the original Duron/Athlon chips.

      Pushing the cpu up from 650 to 800mhz made *all* the difference...
    • Re:Way back when.... (Score:5, Interesting)

      by ookabooka (731013) on Tuesday July 24, 2007 @08:46PM (#19977987)
      Or unlocking certain multipliers [motherboards.org] on your Athlon. . .I never actually did this trick as I used window defogger instead (more reliable as it is more conductive). I still have 2x Athlon 2200xps Bartons overclocked to ~3000xp equivalent and running as MP in a dually of mine. . .super cheap dual-processor machine with craptons of processing power back in the day.
      • Re: (Score:3, Interesting)

        I have a 2x Athlon XP 2400+ Thoroughbred machine using the same XP->MP trick. Though I used conductive paint, because the pencil didn't work for the version of the chip that needed the gap filling in instead of joining the dots on either side.

        It's not as powerful as a modern Athlon 64 X2 3800+ (which is also 2x 2GHz, and I also own), and uses at least four times the power (and produces four times the heat), but I love it because I actually worked to build it instead of slapping together some parts.

        Oh, an
    • Re: (Score:3, Informative)

      by Mal-2 (675116)
      There was a time when you could unlock the multiplier on an Athlon chip with a pencil as well. When AMD went from the ceramic to the "organic" packaging, this no longer worked -- you needed a conductive pen instead, which was still possible, but more error-prone. After all, you can just erase a stray pencil mark, and the silver pen ink tends to spread unless you tape off adjacent areas.

      I don't know if these pens were readily available (though I bet they existed) when you had to repair your old Atari, but on
    • I guess there really *is* no use crying over spilled milk.....
    • by SamLJones (930806)
      I used to use mechanical pencil lead (0.5, if it matters) to short the contacts on a 12-volt lantern battery. Sometimes the lead would get really hot (melted through my plastic desk), sometimes it would glow, once it disappeared completely. I love graphite :-)
    • by Kattspya (994189)
      This doesn't work with modern keyboards or at least not with the pencil and keyboard I used. I had to get conductive silver paint instead and that worked like a charm. It took a while to figure out that the resistance takes a lot of time to drop to nominal levels though (2Mohm? WTF it was only five hundred before I applied this shit).
  • Seeing as buckytubes have enormous conductivity, and are strong under tension, graphene should act similar, providing a far better replacement for silicon and copper. I do not think that the transition will come soon, but this is a great innovation and ahead of its time. I personally think that buckytubes should be looked into in greater detail before attempting graphene.
    • Seeing as buckytubes have enormous conductivity, and are strong under tension, graphene should act similar, providing a far better replacement for silicon and copper. I do not think that the transition will come soon, but this is a great innovation and ahead of its time. I personally think that buckytubes should be looked into in greater detail before attempting graphene.

      Uh...could we possibly be any more generic?

      Since when did re-summarizing the link's summary constitute something "interesting"?

  • I doubt I'd do anything more than pencil this in for somewhere 5 years... no make that 7 years... no, we've really almost perfected it this time...
  • by ShaunC (203807) * on Tuesday July 24, 2007 @07:48PM (#19977437)
    I sort of like seeing the once-a-week news story about how some meth-head electrocuted himself in the process of stealing copper wire to sell for scrap. I'd hate to see the demand for copper go down!
  • So light intensity is measured in candles, will a universal metric for measuring processing power be named 'pencils'?
  • but (Score:5, Funny)

    by inKubus (199753) on Tuesday July 24, 2007 @07:52PM (#19977479) Homepage Journal
    is it carbon neutral?
    • by jswigart (1004637)
      To hell with the environment, I need more fps in my games.
    • Re: (Score:3, Funny)

      by saskboy (600063)
      Not only is it neutral, but it's carbon negative. You'd have a source of carbon right from the CO2 in the air around production ~assuming they can use that carbon efficiently by splitting it from the oxygen. I think they'd just need a chlorophyl machine to do that.
      • ...and a lot of energy. Probably enough to make it unreasonably expensive.
      • You'd have a source of carbon right from the CO2 in the air around production

        Heh, now just combine this with nanobot and neural network technology and you'd have a self improving system, maybe even expanding at Moore's law's speed. You can increase the progress by breathing on it or doing sports in the vicinity. I wonder how many blows it will take until it becomes self-aware ;)

        I think they'd just need a chlorophyl machine to do that.

        I find the idea of organic circuits interesting, but chlorophyl
    • by StikyPad (445176)
      No, but I'll sell you some carbon credits if that makes you feel better.

      Also, by coincidence, your user number was chosen as a winner of a valuable prize in our no-fee lottery! Please remit payment of $5,000 to cover shipping and import duties to receive your prize valued in excess of $100,000.
  • A group at Columbia (some people from Phil Kim's group, I think) published something along these lines in Physical Review Letters back in... May? I don't have access to my copies at the moment, so I don't know for sure. I believe that their paper references an even earlier paper (January?) on arxiv by a group from Thomas Watson. I haven't read the IBM paper, but I remember the Columbia paper being interesting.
  • by Orp (6583) on Tuesday July 24, 2007 @08:47PM (#19977995) Homepage
    When I was younger I used to have fun with a variable transformer that originally was used for a model train set. It had a wiper-type slider that would go from 0 to 12(?) volts from left to right. I discovered by placing the contacts across the graphite in a pencil I could heat the graphite until it glowed cherry red and caused the wood of the pencil to start smoking. Good times.
    • I used to break pencils in two, sharpen a point and shave the wood off the opposite end of each half. Then I'd tape the halves down with the sharpened points nearly touching, and put crocodile clips on the exposed ends.

      Carbon arcs are awesome for retina burns!

      • by Seedy2 (126078)
        Was wondering if anyone would bring up the wonderful carbon arc experiments. In my youth I connected the lamp in my room, with bell wire, to two Scripto mechanical pencils. (.5) and proceeded to melt the interiors completely and trip the breaker the lamp was on. Annoyed everyone, somehow managed not to kill myself, made pretty light show until the lead burned down to the metal tip of the pencil.

        Very not safe, but very entertaining.

        messed up the radio pretty bad for a few seconds too :)

        Ah, to be a child agai
    • Re: (Score:3, Informative)

      by ross.w (87751)
      Also possible to disable someone's car (when they had distributors) by removing the distributor cap and drawing a line from the centre to the outside using a pencil. High voltage tracks the pencil line to ground - car won't start.
    • by geobeck (924637)

      I seem to remember having an electrical experiment kit that included an experiment that used a pencil lead as a variable resistor. This was back in the days when you had to carefully remove the "lead" from the wooden pencil, rather than use a convenient mechanical pencil lead. Anyone else remember doing this?

      • by HTH NE1 (675604)
        It was also a demonstration on an episode of Mr. Wizard [imdb.com] or Mr. Wizard's World [imdb.com], whichever one was on Nickelodeon when it was young. The harder you pushed the lead on the lead (heh), the lower the resistance and the brighter the bulb.
    • by Bazer (760541)
      I made exploding pens out of the stuff. Two wires sticking out of a pen tube, connected inside with pencil graphite (the thicker the better). Stick it in a socket (don't stand on the other end) and watch the sparks and thick black smoke.

      The maintenance man had to carry around a lot of replacement breakers when I was in primary school.
  • I call bullshit (Score:1, Insightful)

    by Anonymous Coward
    Why is it "pencil graphite"? Why not just graphite? Is it because we're all too stupid to know that graphite is used in pencils? Or is there something magical about the graphite found in pencils that makes it particularly useful for making chips? I guarantee that there are no pencils filled with graphene.
    • by TheSHAD0W (258774)
      Actually what we call "graphite" in pencils is actually mostly clay with carbon embedded in it. I don't think the carbon is even mostly in graphite form.
  • Pencil Trick (Score:2, Informative)

    by Taleron (875810)
    A common method for unlocking old Athlon and Duron processors was using a good old pencil to connect the bridges. They're catching on!
  • Imagine a huge coal burning power plant spewing carbon which is then sucked into a chimney next door at the semiconductor processing plant.
    • by eam (192101)
      No, this is how it will work: In a few years the use of carbon in electronics will start to cause shortages. Plants will start to die because they don't have the carbon dioxide they need for photosynthesis. Because electronic devices will *still* end up going to landfills no one will be reclaiming the carbon they use. Scientists will start talking about how we need to burn more fossil fuels to release more CO2.

      Then there will be a long awaited marble [youtube.com] revolution in computing.
      • by HTH NE1 (675604)
        There's a natural response to a lack of CO2 in the atmosphere: it's called a forest fire.

        And if you don't have any forests, there's lots of other combustibles around just waiting to be lit by (name a word with four consecutive consonants) lightning.
  • Where did graphite pencils get mentioned in the article (yup, I even read it). Even Wiki has nothing relating graphene to pencils. /. is turning into a rag with sensationalistic headlines that have nothing to do with the article and often even the summary. The sad part is that the stuff might even be interesting without the "Rabbit Fur wrapped Cat5 outperforms fibre".

    errrr.....

    • Re: (Score:1, Informative)

      by Anonymous Coward
      Sir, Graphite is used in pencils, Graphene is just sheet of Graphite.

      "Graphenes are the 2-D counterparts of 3-D graphite." http://en.wikipedia.org/wiki/Graphene [wikipedia.org]
      "Graphite (named by Abraham Gottlob Werner in 1789 from the Greek (graphein): "to draw/write", for its use in pencils) is one of the allotropes of carbon." http://en.wikipedia.org/wiki/Graphite [wikipedia.org]
      • by bryan1945 (301828)
        Sir, graphite is used in pencils. Graphite is made of carbon. Diamonds are made of carbons. Diamond pencils will now replace electrical wiring.

        Gimme a break- it's still a stupid ass title, and you are just being cranky. I'd say trying to be informative if you were not AC'ing.
  • Graphene, a one-atom-thick sheet of carbon, eluded scientists for years but was finally made in the laboratory in 2004 with the help of everyday, store-bought transparent tape.

    Back in 2002/2003 my son used graphite (pencil-lead) to power an 16 light-bulb saltwater contraption for the science fair.

    Is Graphene the same as graphite? If yes then why in the hell am I not getting paid by the government for the chemistry lab I set up in my computer room?

    Oops, chemistry is fun. We don't need anyone to fund it.

    Enjo
  • IF you have something that conducts electricty that well, and could wind it up, couldn't you theoretically get a really tiny but super powerful electric motor? There's a lot of cool applications that could come from that. For one, I could have a DVD tray on my PC that could actually mix drinks, besides just hold them.
  • by Ancient_Hacker (751168) on Wednesday July 25, 2007 @07:47AM (#19981567)
    Ahem, perhaps these pencil-pushers should talk to actual chip makers and bakers first before speculating on the applications of graphene. Anything that's only one atom thick isn't compatible with current or any forseeable IC process. Chips have to undergo many heating, cooling, deposition, and diffusion steps before they're done. Anything one-atom thick is going to diffuse away in the process. You also have the reliability problem-- you need reliable connections, millions of them. Anything one-atom thick is going to have too many defects.
    • by Richard Kirk (535523) on Wednesday July 25, 2007 @08:35AM (#19981901)

      Yep. They need to cooperate with the silicon chip makers. And that's the really interesting bit...

      Carbon can be a superresistor, a resistor, a semiconductor, or a conductor just by itself. The big, conjugated pi electron clouds you get above and below a graphite layer have lots of electrons in a single ground energy state, much like superconductivity. There are hopes that you can get some reduced dimension superconduction in carbon if you an up the electron density a bit. You may get this inside a buckytube where the curvature gives more electrons per unit volume.electron cloud is You could do this by rolling up a graphene into a buckytube. Then carbon could do the lot, electrically.

      Fine. Carbon is clever stuff. However, we have spent a huge amount of time and effort on silicon. It is one small step on the periodic table, but one great leap for mankind. When we solder a device to a circuit board, there is a whole technology involved in getting from the submicron geometries and tiny singnals to the submillimeter sizes and microamp currents for things we can physically handle. We are going to need a new technology to go from the microscale of silicon to the nanoscale, quantum world of silicon. This could be thirty years of pouring research into new techniques before we ever get a useful device.

      If, however, someone can come up with some way of using carbon on silicon, then we may be able to start working on practical carbon fabrication techniques and make them pay under much shorter timescales. I had always imagined the first application of carbon as some memory unit as memory usually involves banging out billions of copies of the same simple element, so the development costs in designing a single element are allowed to go higher than elsewhere. However, here is another option: we can deposit carbon onto an existing silicon surface - not as genuine epitaxy, but just using it as a flat surface, the way copper currently does. The next trick might be to get the film to roll itself into a buckytube. We have got the connections from silicon to carbon, and just the beginnings of practical self-assembly.

      Whoo-hoo!

  • by Chemisor (97276) * on Wednesday July 25, 2007 @08:43AM (#19981965)
    Bah, Physicists and their QM simulations! They got it all wrong again. It isn't the length of the graphene ribbon that affects its properties, but the shape of its edges. If you look at benzene ring's molecular orbitals, you'll see that there are two ways to pack them in a ribbon. If they all line up, with resonant transfer going along the ribbon in a straight line, then you have metallic conductivity, with the electron just gliding across all the orbitals without hitting any gaps. If the orbitals don't line up, you end up with little dead ends here and there, which cause "turbulence" and reduce conductivity.

    Now, the packing of the orbitals is determined by the edges because of their constraints on orbital orientation. In the middle of the ribbon, you have a pure hex grid, and the orbitals, which can be visualized as taking half of each hex and painting a large C on it (these are not the same as the three bonding pi orbitals). Try it yourself: draw a hex grid and try to pack Cs. To visualize resonance, push on one end of a C and see how to repack the resulting structure. In the middle, you have three orientations at every node, but at the edges you don't. The more edges you have, the more constraints there are on the packing, and the more likely it is that the oribitals in the middle won't be in resonance with each other in a given direction. When you push on a C in such a grid, it will push other Cs sideways instead of along the ribbon, causing "resistance".

    There are two types of edges, familiar to tile game developers as the vertical and horizontal orientation. In the horizontal packing, the flat side of each hex is bordering the edge, in the vertical the flat side is perpendicular to the edge. It turns out that if you have horizontal edges on your graphene ribbon, it is metallic; if you have vertical ones, it is semiconductive (which is another way of saying it has more resistance). If the edges are not quite straight, which will quite likely happen if you are making your ribbons via CVD or duct tape or something, you'll see a mix of both behaviors, resulting in a conductivity somewhere in between full-out and almost-nothing.

    This is the trouble with modern physics - they just don't care about reality any more. If they only drew a few pictures, like real chemists do, they'd have seen this very easily. Instead they waste their time on simulations that only give them numbers they don't know how to interpret. Sheesh.
  • "Pencils son. Pencils." Sorry. The article title is just plain silly.
  • From the article, it sounds like this only works when the graphene conductor size is a few atoms wide and "one atom thick" -- wouldn't quantum effects become a problem at that scale? Does anyone know or have an opinion whether graphene conductors could be used in a "classical" computer or only a quantum one?
    • Yes (Score:3, Informative)

      by marcosdumay (620877)

      "wouldn't quantum effects become a problem at that scale?"

      Quantum effects create the properties those people are looking for.

      • by Bob-taro (996889)

        Quantum effects create the properties those people are looking for.
        I thought at atomic scales there were undesirable quantum effects ... like a significant chance that the electrons will "tunnel" out of the conductor.
  • I realize that they're talking about very, very small wires, but how about the big fat 12 gauge suckers in my wall? The price of copper is going through the roof. Is there any chance we can wire up our house with left over charcoal? I love to see the price of copper drop so we can go back to the days when a penny was actually worth a penny (or less). [nytimes.com]
    • by Whiteox (919863)
      Well my electrical engineering friend once told me that it is only the 'outside' of a wire that actually carries current, so (if that is true), then you could make the wire out of anything, as long as it's plated with copper or other highly conductive material and it'll work the same!
      • I've heard this too-- but it seems like such a big deal that the big power companies would have started exploiting it already. Those long haul power lines must use a ton of copper. If they could save 90% of it, I would guess that they would do that already. But what do I know?
        • Re: (Score:3, Informative)

          by ivan256 (17499)
          They already do. Long haul high-tension wires are copper on the outside, and either aluminum, steel, or composite fiber on the inside.

          Of course, the reasoning isn't what the GP was saying. They actually do it do balance the conductivity with the weight of the wire since the cable needs both high conductivity and the ability to support itself without breaking or sagging too far.
      • by Pyrrus (97830)
        What he's talking about is called skin effect [wikipedia.org]. For alternating current, the highest current density is in the "skin" of the conductor, and it drops off exponentially as you approach the center. For 60Hz, the depth is 8.5mm (at this depth the current density is 1/e or 36.8% of the current density at the skin. So you can't get away with thin copper plating at these frequencies, but power lines are frequently hollow or filled with something like steel, which is a lot cheaper.
        • by Hucko (998827)
          And in the switch yards, most of the fixed 'cabling' looks like your average round metal garden fence post. (Hmmm... with that many qualifiers, does it still constitute average?)
  • Cool, now I can draw my own motherboard, I wonder if you could combine this with different types of lead to make your own special kinds of circuits, but it must suck if you wanna crossover a circuit.

    Would it be cheating on a test if I drew a half-adder or an adder and used it to add stuff up on my calculous tests?

  • by mentaldrano (674767) on Wednesday July 25, 2007 @04:12PM (#19987785)
    There is a lot of interest in graphene these days among physicists - if you're interested, Google "massless Dirac fermion" for more info, or check pretty much any recent issue of Science or Nature.

    The electrical engineers however, have said "meh." Graphene is a decent electrical conductor if you dope it with something - not as good as copper, but decent. It does have great thermal conductivity, though. The big problem with graphene is that you can't really make it in big sheets or long wires. The "tape" method is a great hack - simply stick the tape onto a chunk of graphite, then peel it off and stick it on a substrate (glass or silicon), then peel it off again. Odds are, now you have a sheet of graphene stuck to your substrate, somewhere. Bad news: the biggest piece you're likely to find will be 1-10 micrometers long, and you'll need an electron microscope to find it. This is great for investigating the electrical or thermal properties of graphene, but as for manufacturing, forget it.

    As for graphene transistors, those are out too. Transistors should have a very high resistance when "off," and graphene doesn't. The maximum resistance a sheet of graphene can have is about 6 kiloOhms for a square sheet. Fundamentally, graphene is a semiconductor like silicon or germanium, but its band gap is zero, which basically means it can never be "off."

    'Drano
  • I love science with graphite!

    If you hook up a pencil lead to a transformer, such as that for toy trains, then turn up the power, it will glow red hot. You can then bend it and let it cool down, and poof! You have a bent pencil lead.

    Heat it too much and it has a chemical changeover and stops being conductive.

    Meh, I should have published a paper 30 years ago.

You scratch my tape, and I'll scratch yours.

Working...