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Science Technology

Aussie, Finnish Researchers Create a Single-Atom Transistor 96

Posted by timothy
from the for-small-transitions dept.
ACKyushu writes "Researchers from Helsinki University of Technology (Finland), University of New South Wales (Australia), and University of Melbourne (Australia) have succeeded in building a working transistor whose active region comprises only a single phosphorus atom in silicon. The results have just been published in Nano Letters. The working principles of the device are based on sequential tunneling of single electrons between the phosphorus atom and the source and drain leads of the transistor. The tunneling can be suppressed or allowed by controlling the voltage on a nearby metal electrode with a width of a few tens of nanometers."
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Aussie, Finnish Researchers Create a Single-Atom Transistor

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  • Re:Cosmic rays (Score:5, Informative)

    by calmofthestorm (1344385) on Sunday December 06, 2009 @08:03AM (#30342528)

    Mostly we don't send it into space.

  • Re:Cosmic rays (Score:3, Informative)

    by maxume (22995) on Sunday December 06, 2009 @08:23AM (#30342562)

    I would think you either use the principles involved to make a slightly bigger, less sensitive transistor, or you run 10 or 20 of them in parallel and use the largest consensus.

  • by deglr6328 (150198) on Sunday December 06, 2009 @08:24AM (#30342566)

    Notice that this discovery was NOT published in Nature. Wonder why? Here's why: http://en.wikipedia.org/wiki/Jan_Hendrik_Sch%C3%B6n [wikipedia.org] . Stay skeptical, wait for replication.

  • by mangu (126918) on Sunday December 06, 2009 @09:32AM (#30342794)

    And the mistake begins where a FET(sic) is called a transistor at all.

    Then how would you call a Field Effect Transistor?

    They have merely got as close as possible to a valve

    No. A valve uses charge carriers (electrons) floating in a vacuum. A transistor uses either electrons or holes in a semiconducting solid as charge carriers. A semi-conducting solid is not as close as possible to a vacuum.

  • by Anonymous Coward on Sunday December 06, 2009 @10:35AM (#30343062)

    Then how would you call a Field Effect Transistor?

    Nice try with the bolding of F,E,T. Perhaps, with your use of "how" instead of "what", you are not native English, and don't understand the use of "sic". This is often used to denote a particular term/phrase/whatever which the writer considers incorrect, but which is being quoted nevertheless as-is. The fact that a FET is called a FET doesn't mean it is a transistor, any more than the Democratic People's Republic of Korea is democratic, for the people, or a republic. You thus still call the DPRK the DPRK, as you call a FET a FET, because those happen to be the best-known names, but you don't call the DPRK a "democracy" and you don't call the FET a "transistor".

    Now, the evidence, from the horses's mouth. Read the quote in the left hand column [pbs.org] by the guy who named the transistor. He named it so because it - "it" being the point contact transistor and devices descended from it, such as the modern BJT - had transfer resistance, the dual of the vacuum tube (or FET) which is defined in terms of its transfer conductance. Understand?

    A semi-conducting solid is not as close as possible to a vacuum.

    A substance comprising one atom is as close as possible to a substance comprising no atoms. My comment was somewhat tongue-in-cheek, designed to illustrate the danger of imprecision. In particular, the discovery is /not/ of a one-atom transistor, or even a one-atom FET, it's of a FET with a single atom channel. The other AC seemed to understand this.

  • by Anonymous Coward on Sunday December 06, 2009 @11:14AM (#30343252)

    Mod parent up. mangu has completely missed the point, and so, apparently, have the moderators. A fet is more similar in principle/modelling/use within a circuit to a valve than the transistor, i.e. the BJT (before commercially viable FETs even existed). The only way a FET is more similar to a transistor is the nature of the charge carriers.

    Specifically:
    gate = gate
    cathode = source
    anode = drain

    A depletion mode FET allows current to flow except when the reverse bias voltage between gate and source is such as to increase the depletion enough to pinch off flow. A triode valve typically allows current to flow except when the bias voltage between gate and cathode is such as to repel all electrons back to the cathode. Either way, input resistance is high. Voltages in between vary current flow.

    The basic (BJT) transistor collector-emitter current, meanwhile, is zero unless forward bias is applied on base-emitter. Once your 0.6V is applied, it is mainly base-emitter current which determines collector-emitter current. Input resistance is relatively lower.

    Valves and FETs admit voltage controlled currents. They are primarily defined in terms of trans-conductance.

    Transistors admit current controlled currents. They are primarily defined in terms of trans-resistance.

    I am shocked that /. needs this explained.

  • by windwalkr (883202) on Sunday December 06, 2009 @11:31AM (#30343334)

    I would say it's pretty much lost steam already. If you take a function that can't exploit multiple cores, then the single core performance has not improved much in a while.

    Moore's law does not describe performance. [wikipedia.org]

  • Re:tom (Score:3, Informative)

    by HiThere (15173) <charleshixsn@ e a r t h l i nk.net> on Sunday December 06, 2009 @02:08PM (#30344422)

    FWIW, phosphorous will burn water. It pulls the oxygen away from the hydrogen. So in my high school chem lab it was stored under kerosene instead. Quite mind boggling at the time.

    So if you're going to worry about spontaneous combustion, perhaps you should cool your computer with kerosene rather than water.

  • Re:Cosmic rays (Score:3, Informative)

    by John Hasler (414242) on Sunday December 06, 2009 @10:32PM (#30348534) Homepage

    > So what do we do ?

    We use error correcting codes.

From Sharp minds come... pointed heads. -- Bryan Sparrowhawk

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