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First computer made of carbonnanotubes is unveiled

Discussion in 'Science & Technology' started by micropage7, Sep 29, 2013.

  1. micropage7


    Mar 26, 2010
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    Jakarta, Indonesia
    The first computer built entirely with
    carbon nanotubes has been unveiled,
    opening the door to a new generation of
    digital devices.


    "Cedric" is only a basic prototype but could be
    developed into a machine which is smaller,
    faster and more efficient than today's silicon
    Nanotubes have long been touted as the heir to
    silicon's throne, but building a working computer
    has proven awkward.
    The breakthrough by Stanford University
    engineers is published in Nature .
    Cedric is the most complex carbon-based
    electronic system yet realised.
    So is it fast? Not at all. It might have been in
    The computer operates on just one bit of
    information, and can only count to 32.
    "In human terms, Cedric can count on his hands
    and sort the alphabet. But he is, in the full sense
    of the word, a computer," says co-author Max
    "There is no limit to the tasks it can perform,
    given enough memory".
    In computing parlance, Cedric is "Turing
    complete". In principle, it could be used to solve
    any computational problem.
    It runs a basic operating system which allows it
    to swap back and forth between two tasks - for
    instance, counting and sorting numbers.
    And unlike previous carbon-based computers,
    Cedric gets the answer right every time.
    "People have been talking about a new era of
    carbon nanotube electronics, but there have
    been few demonstrations. Here is the proof,"
    said Prof Subhasish Mitra, lead author on the
    The Stanford team hope their achievement will
    galvanise efforts to find a commercial successor
    to silicon chips, which could soon encounter
    their physical limits.

    Carbon nanotubes (CNTs) are hollow cylinders
    composed of a single sheet of carbon atoms.
    They have exceptional properties which make
    them ideal as a semiconductor material for
    building transistors, the on-off switches at the
    heart of electronics.
    For starters, CNTs are so thin - thousands could
    fit side-by-side in a human hair - that it takes
    very little energy to switch them off.
    "Think of it as stepping on a garden hose. The
    thinner the pipe, the easier it is to shut off the
    flow," said HS Philip Wong, co-author on the
    But while single-nanotube transistors have been
    around for 15 years, no-one had ever put the
    jigsaw pieces together to make a useful
    computing device.
    So how did the Stanford team succeed where
    others failed? By overcoming two common
    bugbears which have bedevilled carbon
    First, CNTs do not grow in neat, parallel lines.
    "When you try and line them up on a wafer, you
    get a bowl of noodles," says Mitra.
    The Stanford team built chips with CNTs which
    are 99.5% aligned - and designed a clever
    algorithm to bypass the remaining 0.5% which
    are askew.
    They also eliminated a second type of
    imperfection - "metallic" CNTs - a small fraction
    of which always conduct electricity, instead of
    acting like semiconductors that can be switched
    To expunge these rogue elements, the team
    switched off all the "good" CNTs, then pumped
    the remaining "bad" ones full of electricity - until
    they vaporised. The result is a functioning circuit.
    The Stanford team call their two-pronged
    technique "imperfection-immune design". Its
    greatest trick? You don't even have to know
    where the imperfections lie - you just "zap" the
    whole thing.

    "These are initial necessary steps in taking
    carbon nanotubes from the chemistry lab to a
    real environment," said Supratik Guha, director
    of physical sciences for IBM's Thomas J Watson
    Research Center.
    But hang on - what if, say, Intel, or another chip
    company, called up and said "I want a billion of
    these". Could Cedric be scaled up and factory-
    In principle, yes: "There is no roadblock", says
    Franz Kreupl, of the Technical University of
    Munich in Germany.

    "If research efforts are focused towards a
    scaled-up (64-bit) and scaled-down (20-
    nanometre transistor) version of this computer,
    we might soon be able to type on one."
    Shrinking the transistors is the next challenge for
    the Stanford team. At a width of eight microns
    (8,000 nanometres) they are much fatter than
    today's most advanced silicon chips .
    But while it may take a few years to achieve this
    gold standard, it is now only a matter of time -
    there is no technological barrier, says Shulaker.
    "In terms of size, IBM has already demonstrated
    a nine-nanometre CNT transistor.
    "And as for manufacturing, our design is
    compatible with current industry processes. We
    used the same tools as Intel, Samsung or
    "So the billions of dollars invested into silicon
    has not been wasted, and can be applied for
    For 40 years we have been predicting the end of
    silicon. Perhaps that end is now in sight.

  2. The Von Matrices

    The Von Matrices

    Dec 16, 2010
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    How this is any better than silicon transistors for future processors? I thought the fundamental problem with process advancement was that, even neglecting leakage, you can't build a transistor smaller than a few atoms. Within 10-15 years a transistor will be made up of fewer than 10 atoms. It doesn't seem like CNTs are any more space efficient than silicon transistors and this problem with shrinking feature sizes will still exist.

    Edit: I reread the article and it refers to CNTs being able to increase switching speed compared to silicon transistors, which would improve performance. But my prior statement still applies, you can't keep shrinking silicon transistors or CNTs indefinitely. The CNT research needs to focus on continuing to increase CNT switching speed at the same time as reducing feature size or else that technology will hit a performance limit around the same time silicon does.

    What I interpret needing to be done within the next 15-20 years to continue increasing performance exponentially is a fundamental change in the method of computation where binary is no longer used, be it quantum computing, DNA computing, or some other technology.
    Last edited: Sep 29, 2013
  3. alexstone New Member

    Nov 4, 2013
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    I affraid this future we are going in
  4. tigger

    tigger I'm the only one

    Mar 20, 2006
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    Can it run Crysis?......................Sorry someone had to.

    Interesting, maybe silicons days are numbered
    10 Year Member at TPU
  5. natr0n


    Jan 29, 2012
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    Boca Raton, Florida
    We need to overclock it to see its potential.

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