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4/25/06 LaBean COMPSCI 296.04
Moletronics
http://www.quinion.com/words/turnsofphrase/tp-mol1.htm
Late 1940s -Mulliken& Szent-Gyorgi’stheory of molecularconduction.
1959 - Feynman 1974 - Ratner &
Aviram proposedmolecular rectifiers.
1999 - first singlemoleculemeasurementsdemonstrated.
4/25/06 LaBean COMPSCI 296.04
Single crystalnanowires (Si, Ge, etc.)
Carbon nanotubes Quantum dots Organic molecules Biomolecules
4/25/06 LaBean COMPSCI 296.04
Scientific American
Break junctions. Electric cut junctions. SAM on curved
electrodes. SPM, STM.
4/25/06 LaBean COMPSCI 296.04
Single electron devices. Single atom switching. Switching by biomolecular
recognition. Spintronics.
4/25/06 LaBean COMPSCI 296.04
Some difficulties in data interpretation
Contact resistance. Multiple conduction mechanisms. Molecular distortions. Specific example: DNA conductivity
Insulator, semiconductor, conductor, superconductor.
4/25/06 LaBean COMPSCI 296.04
Key difficulties to be overcome formolecular circuit design
Scalability to near molecular dimensions. Tolerance of manufacturing defects. Introduction of non-traditional fabrication methods
(e.g. chemically directed self-assembly). Bridging between device densities potentially
achievable at molecular scale with those at forstandard lithography.
Simplicity of fabrication.
4/25/06 LaBean COMPSCI 296.04
Crossbars and demultiplexers
Memory circuitdetails shown.
2n memory bits(black nanowirecrossings) canbe addressedby n pairs ofmicro wires(blue).
MEcomponentslocated atnanowirescrossings.
Binary tree multiplexer