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Hardware Technology

Breakthrough Grows Graphene On Silicon Substrate 60

Posted by ScuttleMonkey from the graphene-farmers-unite dept.
eldavojohn writes "A new paper entitled Epitaxial Graphene on Silicon toward Graphene-Silicon Fusion Electronics published by a group of physicists at Tohoku University in Japan has demonstrated that they can grow graphene on a silicon substrate and pair that technique with conventional lithography to create a graphene-on-silicon field effect transistor. For quite sometime we've been discussing the supermaterial graphene being used like silicon improving everything from memory density to transistors. Given this demonstration, are we witnessing the start of a new era in electronics or are there more hurdles to clear before the manufacturers adopt this fabrication process and embrace graphene?"
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Breakthrough Grows Graphene On Silicon Substrate More

Breakthrough Grows Graphene On Silicon Substrate

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  • Super! (Score:4, Funny)

    by hey! ( 33014 ) on Monday February 01, 2010 @09:18AM (#30980612) Homepage Journal

    "Breakthrough Grows Graphene On Silicon Substrate"? I'm calling everyone I know with the news. In fact, I'm writing my congressman to demand a new three day holiday: "National Graphene On Silicon Substrate Day".

    • Re: (Score:2)

      by Pojut ( 1027544 )

      NGOSS Day? Sounds like a good name to me :P

      • Re:Super! (Score:4, Funny)

        by hey! ( 33014 ) on Monday February 01, 2010 @10:38AM (#30981770) Homepage Journal

        I've been trying to write a poem about the authors of this paper, but I'm having trouble with the scansion.

        "GRAPHene on SILicon SUBstrate" is trochaic triameter, and lends itself to the ballad quatrain, e.g.

        Has ever there been a more wonderful thing,
        than graphene on silicon substrate?
        I'll bet Hyun-Chul Kang doesn't mind it a bit,
        that in college he wasn't a "fun date".

        I've had to drop several of the original 11 authors (HIroKAzu FUkiDOme, RYOta TAkaHASHi, and AKiTASHi YUshiGOe) whose names take up an entire quadrameter line and are hard to rhyme.

        • Re: (Score:1)

          by Jetrel ( 514839 )

          Wow this poem has inspired me to write a Haiku.

          Haikus are easy.
          But sometimes they don't make sense.
          Refrigerator.

          That is all.

    • Your state of excitement indicates that you need to get out more often :)
    • Comment removed based on user account deletion

    • Re: (Score:1)

      by drkim ( 1559875 )
      Why?

      October is already "Graphene On Silicon Substrate Month"

      Don't you ever go to any of the "Graphene Grope" parties?
      Don't you hang decorative substrate sheets all over the house and on your front door?
      Of course, it's irritating when the trash pick-up and mail are delayed because of the GOSS Holidays, but hey... it's a such a great tradition for the kids...

  • Not so great (Score:5, Informative)

    by silverpig ( 814884 ) on Monday February 01, 2010 @09:29AM (#30980770)
    This isn't a huge breakthrough. First, their dirac peaks, while graphene-like, look horrible. This means the quality of graphene they are dealing with is very low. In fact, they don't thermally decompose all of the SiC, so they're still not much different than the SiC decomposition method. Something like this [arxiv.org] method holds much more promise. CVD growth of graphene on a copper substrate and subsequent rapid etching of the copper yields HUGE 30+" sheets of single to tri-layer graphene films.

    • Re:Not so great (Score:4, Funny)

      by BrandonBlizard ( 1007055 ) on Monday February 01, 2010 @10:24AM (#30981552)
      That post was so confusing, it must be really well thought out and informative.

    • Re: (Score:3, Informative)

      by moosesocks ( 264553 )

      True, though this would have been a huge breakthrough 1-2 months ago. The paper you linked to was only published on Dec 30 of last year. Prior to that, we had a method to produce tiny flakes of graphene that required an inordinate amount of time, effort, luck, and scotch tape.

      Also, graphene would be a lot more useful to us if we could produce it inexpensively on a silicon substrate. The copper substrate stuff is a huge step forward, but we'd ideally like to end up being able to directly grow graphene on

  • The answer is yes. (Score:2, Insightful)

    by Duositex ( 620105 )
    Q. "Given this demonstration, are we witnessing the start of a new era in electronics or are there more hurdles to clear before the manufacturers adopt this fabrication process and embrace graphene?"

    A. Yes.

    Why are these two things considered by the submitter to be mutually exclusive?? It is both a potential new era of electronics AND there is the potential that there are hurdles to clear. What's the purpose of trying to editorialize a press release?

  • What's the strength of Graphene? (Score:4, Interesting)

    by wisebabo ( 638845 ) on Monday February 01, 2010 @10:02AM (#30981206) Journal

    I mean isn't graphene basically unrolled carbon nano-tubes? And aren't carbon nano-tubes supposed to be very very (tensile) strong, strong enough to be considered to be usable as the raw material for a practical space elevator?

    If (as another poster claims) 30+" sheets of the stuff can be made, could this stuff (even if slightly impure and not good enough for nano-electronics) be very useful for ultra-lightweight armor, fuel tanks (for a single stage to orbit vehicle), bikeframes... even a space elevator? Or is the fact that it is only a 2D mesh of carbon atoms (as opposed to a 3D "lattice" like diamond) make it substantially weaker?

    I read somewhere that a layer of graphene a single atom thick is able to hold back 1 atm. of pressure. Isn't that roughly equivalent to a tissue paper holding back the ocean at some very deep depth (I know this is very imprecise! :)

    • Re: (Score:3, Informative)

      by WillDraven ( 760005 )

      According to this [unitconverterpro.com] 1 atmosphere = 33.932446552 feet of water.

      • I KNOW THAT! (Score:3, Insightful)

        by wisebabo ( 638845 )

        Or at least I thought I did, (for some reason I thought 1 atmosphere = 32ft. water :)

        What I meant to say is that think of the relative strength of a mesh A SINGLE ATOM THICK (sorry for the caps, I don't know how to do italics) being able to hold back the incredible number of molecular impacts one atmosphere of pressure implies. If you layered this mesh to be much much thicker so that it actually was macroscopic in thickness (like a tissue paper) it would be millions (billions? trillions?) of atoms thick.

      • Ah, but is that salt water or fresh?

    • Re:What's the strength of Graphene? (Score:4, Informative)

      by silverpig ( 814884 ) on Monday February 01, 2010 @10:42AM (#30981838)
      Sort of. Actually, it's probably more accurate to say that nanotubes are rolled-up graphene. And yes, graphene is extremely strong. I've seen sheets of it cantilevered out over tens of microns. This is roughly equivalent to taking a sheet of normal paper, holding it in your hands, and having it stick out for well over a football field away from you, perfectly rigid. As strong as it is per unit thickness it is extremely thin (0.34 nm is the number usually quoted), so the total strength isn't useful for armor. After all, graphite is just this stuff layered up millions of times. The 2D mesh is what makes it stronger than diamond because the sp2 bonds are stronger than the sp3 bonds in diamond are.

      • Thanks for the response! Unfortunately I still don't understand, I'm not a chemist/theoretical chemist/physicist (obviously). I didn't think about the fact that graphite isn't good for armor (good point!). Why not? Is it that there are too many defects so it fragments on a nano scale? Or is because there is no "glue" between the layers and that makes them slide around too much (I remember enough chemistry to know that's how pencils work!).

        I never knew that there could be a difference between unit thick

        • Re:What's the strength of Graphene? (Score:4, Interesting)

          by silverpig ( 814884 ) on Monday February 01, 2010 @11:35AM (#30982650)
          It's basically due to the fact you outlined: While the carbon atoms in each sheet are bonded to each other very well, the bonding between sheets is very weak. I suppose you could make "pure" graphite (although pure is not the right word), and have perfect sheets stacked on each other to make a piece of graphite similar to a phonebook, however normal graphite has little flakes of graphene all stuck together somewhat haphazardly. In terms of thickness, sure it's as you say (roughly), that you can double the strength by doubling the layers but just because something has a good tensile strength doesn't mean it is ideal for armor. I am not an armor expert by any means so I'll not comment further. Besides, there are cooler things to do with graphene than make armor :) Well my graphene researching days are over now, but I keep an eye on things due to personal interest.

        • Re: (Score:3, Interesting)

          by Cytotoxic ( 245301 )
          Because graphene is really, really slippery. Two sheets of graphene will slide over each other with very little friction. This is why you can use graphite powder as an effective dry lubricant. This is similar to the problem with using carbon nanotubes as a structural material. You have a very hard time reaching the theoretical strength of the tubes or sheets into the material as a whole because they don't bond well to anything, particularly not each other. If you could figure a way to polymerize graphe

      • After all, graphite is just this stuff layered up millions of times

        Correct me if I'm wrong, but isn't graphite very small fragments of graphene layered on each other? My understanding was that writing with a pencil is just rubbing off the little flecks of graphene. If you layered larger sheets, even a few square centimetres, and layered them more regularly, wouldn't you get something stronger?

        • Re: (Score:2, Informative)

          by silverpig ( 814884 )
          Yeah pretty much. The research I did with graphene was on the "micromechanical cleavage" method (no, not small robot boobs). Basically we'd take a flake of graphite maybe 1mm square, then thin it using scotch tape and then press the tape to a silicon wafer. You can then hunt around for graphene flakes if the wafer has an appropriate thickness of oxide grown on it. The graphene flakes you find in this method are generally 10 square microns, but you can get some that are about 60 microns by 40 microns or so o

    • Re: (Score:2)

      by Zerth ( 26112 )

      If you made a sheet of graphene the thickness of tissue paper, it could possible hold back the ocean. I don't know about straight up graphene, but a sheet of graphene oxide has a tensile modulus of 32 gigapascals.

      On the other hand, you can snap it by folding sharply.

    • What's the point of carbon nano-tubes in computers? I want my interwebz fed through carbon Mega-tubes!

  • 2006 called... (Score:5, Informative)

    by Goldsmith ( 561202 ) on Monday February 01, 2010 @10:06AM (#30981264)

    Oh hey, 2006 called, and they want their science [sciencemag.org] back.

    This field moves *fast* and the epitaxial technique is already being commercialized by IBM (perhaps others too, but IBM isn't hiding it). It's already moving out of science and into manufacturing (for what purpose, I'm not sure anyone knows). Meanwhile, cheaper and larger scale methods to grow graphene have been invented, and are nearly perfected.

    • Re: (Score:3, Informative)

      by John Hasler ( 414242 )

      The Science article is about graphene on silicon carbide. This article is about graphene on elemental silicon. Very different.

      • No it's not. The new article is also about graphene on SiC, they just stuck the silicon carbide to a silicon wafer. This does not make the process cheaper or easier.

    • Re:2006 called... (Score:5, Informative)

      by the Atomic Rabbit ( 200041 ) on Monday February 01, 2010 @11:12AM (#30982248)

      The difference between the 2006 work and this one is that the present researchers are not growing graphene on a silicon carbide substrate, but on a silicon substrate with a silicon carbide thin film on top. This may make it a little more commercially feasible.

      However, the trouble with the epitaxial technique is that no one (AFAIK) has successfully demonstrated a quantum Hall effect [wikipedia.org] in these graphene sheets, unlike the sheets made using the usual "scotch tape" methods. So there's some doubt about whether what they are getting is really graphene. I don't think the present work addresses this problem either.

      • Actually, a quantum hall effect has been observed in epitaxial graphene, and the resistance quantization is four orders of magnitude [nature.com]closer to the quantum h^2/e than in the exfoliated "scotch tape" graphene. You need to keep up on your Nature reading, sheesh!

        The real problem is that the band gap is still zero. These things have an on/off ratio of the order of 10 or less, orders of magnitude worse than Si, the material they are supposed to supplement.

  • The original posting is lacking something very important - an explanation of why this is important. What benefits, if any, are there to being able to do this? Will it lead to faster or more power efficient processors? Will it result in tastier waffles? Will it bring about world peace?

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