Better carbon nanotube transistors

from the shrinking-the-gap dept.
Gina Miller writes "An article summarizing progress with carbon nanotube field effect transistors is available on the nanotechweb.org web site. Nanotubes speed up, by Adrian Bachtold, which originally appeared in the August issue of Physics World, reports that 'Transistors fabricated from carbon nanotubes now have electrical characteristics that can rival silicon devices.'" Briefly, the first nanotube FET, reported in 1998, produced very poor performance so that it could not amplify a signal nor control a second transistor, and thus these FETs could not be integrated into circuits. A new layout for a carbon nanotube FET recently reported by Avouris's group at IBM remedies these problems by "making the resistance much more sensitive to variations in the gate voltage." Various other improvements have been reported by Avouris's group and by several other groups. The most serious remaining problems that prevent manufacture of carbon nanotube circuits are that "it is still impossible to control the electrical properties of synthesized nanotubes," and that it is not yet possible to place "the tubes in predetermined positions during device fabrication."