[Paleopsych] New nanoswitch technology
shovland at mindspring.com
Fri Apr 22 13:32:05 UTC 2005
Switching to chemistry
Researchers at the Weizmann Institute of Science have demonstrated a new
kind of electrical switch, formed of organic molecules, that could be used
in the future in nanoscale electronic components.
Their approach involved rethinking a phenomenon that drives many of today's
high-speed semiconductors. Negative differential resistance (NDR), as the
phenomenon is called, works contrary to the normal laws of electricity, in
which an increase in voltage translates into a direct increase in current.
In NDR, as the voltage steadily increases, the current peaks and then drops
off, essentially allowing one to create a switch with no moving parts. But
until now, those attempting to recreate NDR at the molecular scale had only
managed it at extremely low temperatures.
Prof. David Cahen of the Institute's Materials and Interfaces Department
and graduate student Adi Salomon thought research carried out by Salomon
and others in Cahen's lab during her M.Sc. studies on connections between
metal wires and organic (carbon based) molecules might hold part of the key
to usable nanoscale NDR. They had found that, like people, molecules and
metal wires need chemistry between them for barriers to be lowered and the
juice to really flow. For a given voltage, if the molecules are held to the
wire by chemical bonds (in which the two are linked by shared electrons),
the current flowing through them will be many times higher than if they are
only touching a mere physical bond.
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