Oct 19, 2006
Nanowires get reconfigured
Electric programmability has been the basis for decades of advances in computer component performance. However, once fabricated or assembled, such components - whether blade servers in a data centre or microprocessors on a circuit board - are typically stuck in place and require human intervention for reconfiguration, removal or replacement.
For continued advances at the architectural level, mechanical programmability of components may also be needed. Potential future applications that would require mechanically programmable components include brain-like networks of nanostructure-based artificial synapses, breadboards for rapid prototyping of nanodevice circuits, and fault-tolerant logic in which broken subsystems are replaced automatically from a reservoir.
One generally promising approach for electromechanical manipulation at the nanoscale and microscale is "dielectrophoresis" - the net force experienced by a neutral dielectric object in a non-uniform electric field. In recent work at Harvard University, US, published in Nanotechnology, researchers demonstrated for the first time that dielectrophoresis may be used to assemble, reconfigure, and disassemble some of the simplest nanoelectronic components: nanowire interconnects.
Doped silicon nanowires were suspended in a viscous solvent, which was then pipetted onto a chip with tapered electrodes. The team developed a field pulsing technique for pulling down the nanowires out of solution to electrically connect the electrodes, to reconfigure them, and to disassemble them.
The scientists say the next challenge will be to broaden the selection of useful nanoscale structures and devices that may be dielectrophoretically reconfigured.
About the author
Alexander Wissner-Gross holds degrees in physics, electrical engineering, and mathematics from MIT, US, and is currently a Hertz Fellow, completing his PhD in Physics at Harvard University, US.