july 29/30darpa-meeting1 technological basis fundamental physics device applications ion channels,...

July 29/30 DARPA-meeting 1

Technological BasisTechnological BasisTechnological BasisTechnological Basis

Fundamental PhysicsFundamental PhysicsFundamental PhysicsFundamental Physics

Device ApplicationsDevice ApplicationsDevice ApplicationsDevice Applications

Ion Channels, Carbon Nanotubes, wet/dryIon Channels, Carbon Nanotubes, wet/dry


Technological BasisTechnological Basis

Fundamental PhysicsFundamental Physics

Device ApplicationsDevice Applications


wet/dry/interfacewet/dry/interface

Bio-ChannelsBio-Channels NanotubesNanotubes

The technological basis is provided by nature

The increased knowledge in the chemistry and physics of Ion Channels (location of fixed charges etc.) permits progress in simulation and to learn from nature






NanotubesNanotubes

Synthetic techniques are in infancy

• Laser-ablation (expensive)• Arc-evaporation (MWNT)• CVD in chamberwill give soot to be purified• CVD on chipwill give NTs in desired locations

- Need for control of structure of a single tube

Bio-ChannelsBio-Channels


The increased knowledge in the chemistry and physics of Ion Channels (location of fixed charges etc.) permits progress in simulation and to learn from natureNanotubes grow from CoSi islands






As a self-organized structure, tubes have various symmetry and controllable electronic properties




NanotubesNanotubes







Characterization e.g. by Tunneling Spectroscopy




As a self-organized structure, tubes have various symmetry and controllable electronic properties

NanotubesNanotubes







Bio-ChannelsBio-Channels NanotubesNanotubes

Classical vs. Quantum Mechanical Description

• Casimir Forces at nanoscalequantum electrodynamical description - full microscopics vs. continuum theory

pp11

pp22

EE

J.D.van der Waals, 1873. J.D.van der Waals, 1873. F. London, 1930F. London, 1930H.B.G. Casimir, 1949H.B.G. Casimir, 1949






NanotubesNanotubes

pp11

pp22

EE



• Casimir Forces at nanoscalequantum electrodynamical description - full microscopics vs. continuum theory

J.D.van der Waals, 1873. J.D.van der Waals, 1873. F. London, 1930F. London, 1930H.B.G. Casimir, 1949H.B.G. Casimir, 1949






Bio-ChannelsBio-Channels NanotubesNanotubesClassical vs. Quantum Mechanical Description

Multiple scales in modeling• Equations of Continuity






Bio-ChannelsBio-Channels NanotubesNanotubesClassical vs. Quantum Mechanical Description

Multiple scales in modeling• Equations of Continuity• Monte-Carlo solution of the Boltzmann transport equation• Finite size of the ions !!• Quantum Effects : van der Waals, Casimir, DFT






NanotubesNanotubes


-3 -2 -1 1 2 3

-3

-2

-1

1

2

3

-6 -4 -2 2 4 6

-3

-2

-1

1

2

3

Bio-ChannelsBio-ChannelsClassical vs. Quantum Mechanical Description

Multiple scales in modeling• Equations of Continuity• Monte-Carlo solution of the Boltzmann transport equation• Finite size of the ions !!• Quantum Effects : van der Waals, Casimir, DFT






NanotubesNanotubes

Multiple scales in modeling


• Continuum theory of elastic deformationswith Molecular Dynamics for parametrization• Classical electrostaticswith atomistic quantum capaciatnce• van der Waals

Nanotube Electromechanical Switch

0 10 20 30 40z,nm

0

0.2

0.4

0.6

0.8

, e/

nm

Charge Density Profile




Device ApplicationsDevice ApplicationsDevice ApplicationsDevice Applications






Bio-ChannelsBio-Channels Nanotube FETsNanotube FETs

High ION/IOFF ratio (approaching infinity)

Operation voltage: low

Device characteristics: slow






Nanotube FETsNanotube FETs

Significant improvement (105) of ION/IOFF ratio was claimed in 4 years

Best NT-FETs operate as unconventional SB-FET

S.J. Tans, 1998. S.J. Tans, 1998. Ph. Avouris, 1998.Ph. Avouris, 1998.

C. Dekker, 2001. C. Dekker, 2001. Ph. Avouris, 2002.Ph. Avouris, 2002.


High ION/IOFF ratio (approaching infinity)

Operation voltage : low

Device characteristics : slow







Significant improvement (105) of ION/IOFF ratio was claimed in 4 years










Significant improvement (105) of ION/IOFF ratio was done in 4 years


Sub-threshold slope ??



High sensitivity to oxygen

Nanotube artificial ion-atom- molecule channels





ConclusionsConclusions

Powerful multi scale simulation approaches to both Biological Ion Channels and Carbon Nanotubes possible in near future

Both areas can learn from each other; the wet-dry interface being of particular interest

Interesting device opportunities: low power off/on -> 0

molecular transport in dry world

july 29/30darpa-meeting1 technological basis fundamental physics device applications ion channels,...

Documents

quantum effects

naturethe increased

selforganized structure

various symmetry

control of structure

naturetechnological

lowdevice characteristics

infinityoperation voltage