Transcript Nano-transistors Sensitive to Vibrations in a Single Molecule

NSF/MRSEC Program Nugget
Liquid Nanoparticles
Nanoparticles of many materials have been
prepared in the laboratory and all are very
fine powders in pure form. We have
discovered that nano-particles below a
certain size can be transformed into pure
liquids by attaching the right molecules to
the surface of each particle. The addition of
a second, normally liquid substance like
water or alcohol is not needed.
The nano-liquids will enable new applications of nano-particles to materials technologies. For
example, these liquids could be blended with polymers to change the mechanical or optical
properties of the polymer. Furthermore, nanoparticles in liquid form can be deposited as more
uniform films or coatings than is possible by the current practice that uses suspensions of
nanoparticles in water or, more frequently, organic solvents. Since the melting temperature can be
readily controlled by changing the molecules on the surface, films can be deposited while hot and
then solidified on cooling. Alternatively, the liquid films can be solidified by cross-linking the
molecules by ultraviolet irradiation. The elimination of organic solvents in such processes will enable
“green” nano-manufacturing processes.
Release April 2004. Sogah, Giannelis
For more details, visit the Cornell Center for Materials Research website at:
http://www.ccmr.cornell.edu/news
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NSF/MRSEC Program Nugget
Molecular Transistors
Molecular devices might enable the
manipulation of single electrons on
the smallest possible device length
scales. A cross disciplinary group at
Cornell has demonstrated for the
first time a transistor device that
reaches the ultimate limit in which
an electron hops on and off a single
atom between two contacts. This
has been achieved by nanofabricating gold (Au) electrodes
separated by a very narrow gap.
A single molecule containing a cobalt atom in a well-defined and deliberately designed bonding
configuration is then incorporated into the gap. The electrical characteristics of the transistor can be
varied systematically by making chemical changes to the molecule. This work represents two
significant steps forward in the field of molecular electronics: the ability to design the electronic
states of a molecular device using chemical techniques, and the ability to measure the properties of
individual molecules.
Release April 2002. Abruna, McEuen, Ralph
For more details, visit the Cornell Center for Materials Research website at:
http://www.ccmr.cornell.edu/news
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