Frozen lightning: NIST's new nanoelectronic switch
Researchers at the National Institute of Standards and Technology (NIST) have demonstrated a prototype nanoscale electronic switch that works like lightning—except for the speed. |
Silver would be a natural choice for nanoscale and microscale electrical contacts because of its high conductivity, but it has one notorious drawback. In an electric field, silver ions readily form silver "whiskers," tree-like branching growths of crystals that can short-out microelectronic devices.
Two NIST researchers have demonstrated that this can be a feature, not a bug, in an elegant experiment that uses this growth to make a nanoscale binary switch. In the experiment, |
As a candidate logic switch for nanoscale memory circuits and similar devices, the silver whisker switch has several attractive features:
The chemistry of the organic monolayer is not critical; the switch works with many different molecules and so can be used with many different self-assembled molecular electronics systems.
The crossed-wire structure is very simple to engineer and lends itself to large arrays of switches.
The difference between "on" and "off" is huge—electrical resistance ratios of a million or more. This makes it easier to reliably scale up the technology to very large arrays.
Problems to be overcome, according to the researchers, include volatility—the voltage has to be kept on to retain the switch state; slow switching speeds—about 10 kilohertz in the prototype; and a tendency of the switch to freeze permanently closed after a large number of cycles. ###
NIST has applied for a patent on the switch.
*J.M. Beebe and J.G. Kushmerick. Nanoscale switch elements from self-assembled monolayers on silver. Applied Physics Letters 90, 083117 (2007). Posted online Feb. 23, 2007.
Contact: Michael Baum michael.baum@nist.gov 301-975-2763 National Institute of Standards and Technology (NIST)
Technorati Tags: nanofibers or Nanoscientists and Nano or Nanotechnology and nanoparticles or Nanotech and nanotubes or nanochemistry and nanoscale or nanowires and Nanocantilevers or nanometrology and nanoelectronic switch or National Institute of Standards and Technology and microelectronic devices or nanoscale memory circuits
No comments:
Post a Comment