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IBM researchers have made an important breakthrough: arranging nanotube transistors for complex circuits.

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  • Debajyoti Sarangi
    IBM researchers have made an important breakthrough: arranging nanotube transistors for complex circuits. Researchers at IBM have overcome an important
    Message 1 of 2 , May 29, 2006
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      IBM researchers have made an important breakthrough: arranging nanotube transistors for complex circuits.

      Researchers at IBM have overcome an important obstacle to building computers based on carbon nanotubes, by developing a way to selectively arrange transistors that were made using the carbon molecules. The achievement, described in the current issue of Nano Letters, could help make large-scale integrated circuits built out of carbon nanotubes possible, leading to ultrafast, low-power processors.
      For decades, the size of silicon-based transistors has decreased steadily while their performance has improved. As the devices approach their physical limits, though, researchers have started looking to less conventional structures and materials. Single-walled carbon nanotubes are one prominent candidate -- already researchers have built carbon nanotube transistors that show promising performance (see The Nanotube Computer). According to estimates, carbon nanotubes have the potential to produce transistors that run 10 times faster than even anticipated future generations of silicon-based devices, while at the same time using less power.
      But so far research in the field has hit a roadblock: not being able to control the placement of nanotube transistors, making it impossible to build complex integrated circuits. "The way most [nanotubes transistors] are made now, nanotubes are randomly dispersed on a surface in solution, then source and drain contacts are randomly printed using lithography, and then you search around until you find by chance a tube that goes between a source and a drain," says James Hannon, one of the researchers involved with the work at IBM's T.J. Watson Research Center in Yorktown Heights, NY.
      To gain control over the arrangement of transistors, the IBM researchers coated the nanotubes with molecules that bind only to patterns of metal oxide lines on a surface, and not to the areas in-between.
      To make working transistors, the researchers laid down lines of aluminum using a lithography technique. These wires serve as the gates that turn the transistors on and off. They then oxidized the aluminum to form a thin aluminum oxide layer on top of the wires, which acts as both a dielectric and the material to which the nanotubes will bind. After applying carbon nanotubes in solution and allowing them to bind to the aluminum oxide, the researchers deposited palladium leads perpendicular to the aluminum/aluminum oxide wires. These leads crossed over the nanotubes, becoming the source and drain of the transistor.
      Source: http://www.technologyreview.com/read_article.aspx?id=16931&ch=nanotech





      Dr. Debajyoti Sarangi,
      Micro and Nanosystems, ETH Zentrum –CLA H 1
      Tannenstrasse 3, 8092 Zurich, Switzerland.
      Ph: +41 1 632 27 82 (Office) Fax: +41 1 632 14 62
      Web: http://sarangi.tophonors.com/

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    • Wayne Richardson
      wow! has anyone compared viral/bacterial material vectoring to this? debayoti s post seems like the most accurate way. along these lines... has anyone ever
      Message 2 of 2 , Jun 2, 2006
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        wow! has anyone compared viral/bacterial material vectoring to this?
        debayoti's post seems like the most accurate way. along these lines... has
        anyone ever heard of using sound to create a lattice? the material could be
        either placed in a solution, held magnetically, or in microgravity. i'm not
        sure how it would work at a nano scale.. the sound may have to be very high
        pitched or extremely loud.

        debayoti's post>>>To make working transistors, the researchers laid down
        lines of aluminum using a lithography technique. These wires serve as the
        gates that turn the transistors on and off. They then oxidized the aluminum
        to form a thin aluminum oxide layer on top of the wires, which acts as both
        a dielectric and the material to which the nanotubes will bind. After
        applying carbon nanotubes in solution and allowing them to bind to the
        aluminum oxide, the researchers deposited palladium leads perpendicular to
        the aluminum/aluminum oxide wires. These leads crossed over the nanotubes,
        becoming the source and drain of the transistor.
        Source:
        http://www.technologyreview.com/read_article.aspx?id=16931&ch=nanotech


        [Non-text portions of this message have been removed]
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