Nanotube circuits and more at APS conference

from the Totally-tubular dept.
brian wang writes "Speaking at an American Physical Society meeting in Seattle, Phaedon Avouris of IBM described the creation of a carbon nanotube integrated circuit, with a thousand nanotubes acting like transistors . . . Speaking at an APS meeting in Seattle, Avouris described how, in a mixed batch of nanotubes, one can short out the metallic nanotubes (with a surge of voltage) while leaving the semiconducting ones intact for use as circuit elements."

But, as DanKindsvater notes, AIP Physics News later ran this correction about this item: "Researchers at IBM have not yet made an integrated circuit of carbon nanotubes . . . Rather, Phaedon Avouris and Philip Collins of IBM have announced a scheme for the fabrication of large arrays of nanotubes. They also put together one p-type nanotube transistor and one n-type transistor to form a working logic NOT gate."

Read more for other highlights in nanotube research reported at the APS conference. Other nanotube highlights from the same APS conference:
"- David Tomanek of Michigan State said that experimental measurements of nanotube heat conductivity went as high as 3000 watts/m/K, almost as high as that of diamond. He predicted that nanotube performance would reach levels of 6600 watts/m/K. The ability to conduct heat will come in handy for future circuits needing to dispose of lots of heat from tight places.
– Mathieu Kociak of the CNRS lab, University of Paris-South, announced the first observation of superconductivity in nanotube ropes (see also Kociak et al., Physical Review Letters, 12 March 2001). The researchers hope to raise the transition temperatures, presently only 300-400 mK, through judicious doping.
– John Hafner of Harvard reported using single nanotubes as extensions on the ends of atomic force microscope probes. Not only does this narrow the probe profile, resulting in greater spatial resolution when imaging a variety of biomolecules (such as immunoglobulins) but, when used to seek out specific molecules on a sample surface, the nanotube probe could help in studying tip-sample adhesion. Hafner referred to this approach as "chemical force microscopy" (CFM).
– Finally, Masako Yudasaka of the NEC lab in Japan reported on the enormous pressures that arise when C60 molecules are encased inside nanotubes (an arrangement called "peapods" the force on the C60 is only a nano-Newton, but by dividing by the area of the tube, one arrives at a pressure of .1 giga-Pascal. In other words the buckyball can act like a piston for facilitating novel forms of tailored chemistry. Yudasaka also described her work with nanotubes that flare out like cones (typical size: 2 nm small diameter, length of 50 nm, and opening angle of 20 degrees). These "nano-horns" might be useful for absorbing gases (replacing other forms of activated carbon in filters)."

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