From: Max More (maxmore@primenet.com)
Date: Fri Aug 29 1997 - 11:18:14 MDT
PHYSICS NEWS UPDATE
The American Institute of Physics Bulletin of Physics News
Number 333 August 26, 1997 by Phillip F. Schewe and Ben
Stein
TRAPPING A SINGLE NANOPARTICLE BETWEEN TWO
ELECTRODES has been controllably achieved for the first time,
enabling researchers to deposit individual nanoparticles onto
surfaces and offering possibilities such as single-nanoparticle
switches. Researchers (Cees Dekker, Delft University of
Technology, dekker@qt.tn.tudelft.nl) construct a circuit
containing two platinum electrodes separated by as little as 4
nm--a gap that the researchers believe to be a world record. To
trap nm-scale molecules or clusters, they immerse the electrodes
in a solution containing the nanoparticles. Applying a voltage to
the electrodes polarizes each particle and attracts a particle to the
gap between the electrodes. Once a particle bridges the gap,
current flows through the circuit, and a resistor then sharply
reduces the electric field, discouraging any additional
nanoparticles from entering the gap. In principle, this
electrostatic-trapping technique can work for any polarizable
nanoparticle; it has been demonstrated for nanometer-scale
clusters of palladium (Pd) atoms, carbon nanotubes, and a 5
nm-long chain of thiophene (a conducting polymer). The
researchers have also studied the properties of single electrons as
they cross a Pd nanocluster between the electrodes. (A.
Bezryadin et al., Applied Physics Letters, 1 September; images at
www.aip.org/physnews/graphics)
This archive was generated by hypermail 2.1.5 : Fri Nov 01 2002 - 14:44:47 MST