Transcript Molecular Computing - The University of Oklahoma

Molecular Computing
by Jason Bryant
and
Richard Overstreet
Why do we need smaller
computers?
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Increased Complexity=Increased Computing
Power
To achieve this complexity, the components of
a computer must be made smaller.
There are both practical and scientific
limitations on current silicon-based
technology (Moore’s Law)
One solution lies in molecular switches
What is a molecular switch?
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The use of molecules to construct
electronic components that perform the
same function as a macroscopic
counterpart.
Wires, logic gates, memory circuits, etc.
What kind of molecule do we
need?
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What do we need it to do?
Ideally, transmit or store electrons
Need an empty low energy orbital
Can create a "pi-conjugated system"
Pi Conjugated system
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These pi bonds act as wires by allowing
the passage of electrons
www.d.umn.edu/~pkiprof/chemweb/ Overlap/overlap2.html
Benefits of the Molecular
Switch
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Obvious size advantage
High current flow generates little heat
Self-Assembly=Cheap, identical
production in mass quantities
High potential circuit density
Non-volatile RAM
Need more than just wires
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Need Transistors
Exploiting the pi orbital overlap
Now we have the concepts, how do we
use it?
Mark Reed and James Tour
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Base molecule was the Benzine Ring
http://www.sciam.com/2000/0600issue/0600reed.html
Properties of Benzine Dithol
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Allowed for trapping
of electrons
Varying voltage
controlled
conductive and
nonconductive state
http://www.sciam.com/2000/0600issue/0600reed.html
How could they turn it on and off?
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Addition of NO2 and NH2 to the center
ring created asymmetry that allows for
twisting with applied voltage.
http://www.sciam.com/2000/0600issue/0600reed.html
So how did they build it?
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Self assembly
Need to be able to
attach to metal
surfaces
Addition of thiols.
http://www.sciam.com/2000/0600issue/0600reed.html
Self Assembly Process
http://www.sciam.com/2000/0600issue/0600reed.html
Help from Photolithography
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For now, help from current
semiconductor technology
Creates selected regions for self
assembly
Now we have something resembling
current computer architecture
Hurdles
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The Molecular
Transistor- under
development
Connecting molecular
switches
Logic Gates
Notes
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Mark A. Reed and James M. Tour “Computing
with Molecules” Scientific American June
2000 http://www.sciam.com/2000/0600issue/0600reed.html
Ben Feringa, editor. Molecular Switches
(Wiley-VCH: New York) 2001
David Rotman “Molecular Computing”
Technology Review May/June 2000
University of Minnesota Inorganic Chemistry
Website www.d.umn.edu/~pkiprof/chemweb/
Overlap/overlap2.html 2001