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Clocked Molecular Quantum-dot Cellular Automata

Clocked Molecular Quantum-dot Cellular Automata. A NEW COMPUTATIONAL PARADIGM. Gabriele Dura. Clocked Molecular Quantum-dot Cellular Automata. Recent computation is achieved thanks to the enormous number of C-MOS per area Now there is a problem to continue this trend.

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Clocked Molecular Quantum-dot Cellular Automata

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  1. Clocked Molecular Quantum-dot Cellular Automata A NEW COMPUTATIONAL PARADIGM Gabriele Dura

  2. ClockedMolecular Quantum-dot Cellular Automata • Recent computation is achieved thanks to the enormous number of C-MOS per area • Now there is a problem to continue this trend

  3. Clocked Molecular Quantum-dot Cellular Automata • The Moore’s Law

  4. Clocked Molecular Quantum-dot Cellular Automata • It is necessary a new computational paradigm • Quantum-dot Cellular Automata

  5. Clocked Molecular Quantum-dot Cellular Automata • What is it?

  6. Clocked Molecular Quantum-dot Cellular Automata • How to use it? We can make quantum wire Quantum inverter Quantum Majority Gate Quantum fanout

  7. Clocked Molecular Quantum-dot Cellular Automata • How does it work? Every cell has two extra charge, that could be electrons or holes. Coulombic interaction between this extra charge will achieve a ground state in the cell, moving in the cell by tunneling The two extra charges are confined in the cells by a high potential barrier.

  8. Clocked Molecular Quantum-dot Cellular Automata • These devices have some problems: • Too low working temperature (4°K) • A metastable configuration with long life time can be achieved ERROR IN COMPUTATION • High sensitiity to the position cell-to-cell (showing by simulation)

  9. Clocked Molecular Quantum-dot Cellular Automata • How to solve this problem: • Temperature Molecular Quantum-dot cells • Metastable configuration four phase clock and quasi-adiabatic transition • Imperfections actually there is no indication about (only simulation)

  10. Clocked Molecular Quantum-dot Cellular Automata • Molecular quantum-dot proposed by Lent – Isakcsen Allyl Alkyl

  11. Clocked Molecular Quantum-dot Cellular Automata • Allyl groups serve as dots with his red-ox centre that can be achieved cy halls • Alkyl groups serve as tunnel barrier that halls can pass through

  12. Clocked Molecular Quantum-dot Cellular Automata • Molecule was driven by a driver dipole and clocked by a perpendicular electric field This give a highly nonlinear dipole moment 6.6Å

  13. Clocked Molecular Quantum-dot Cellular Automata • Molecular Quantum-dot Cell

  14. Clocked Molecular Quantum-dot Cellular Automata • It is possible to enable the clock in this device using some buried wires • The current flow through wires generates an Electric Field that drives the state of the molecule

  15. Clocked Molecular Quantum-dot Cellular Automata Clock must have four-phase that allows quasi-adiabatic interaction cell-to-cell Applied Signal Value of Electric Field Electric Field Distribution That implies this “truth table”

  16. Clocked Molecular Quantum-dot Cellular Automata • Influence of imperfection on the dynamical response in QCA Nowadays only considered in model simulations. Ideal chain of cells: Imperfection introduced between the fifth and the sixth the third and the fourth the driver and the chain Correct polarization Acceptable polarization Capability whole disappears

  17. Clocked Molecular Quantum-dot Cellular Automata • Imperfection due to interdot distance defects Imperfection introduced in the interdot barriers in the second cells Dependence of the output cell Response of polarization with this imperfection on the tunneling parameter L1 in the second cell of this chain

  18. Clocked Molecular Quantum-dot Cellular Automata • Imperfection due to interdot distance defects Imperfection introduced in the interdot barriers in the middle cell Imperfection introduced in the interdot barriers in the last cell

  19. Clocked Molecular Quantum-dot Cellular Automata •  Conclusion: We can see that Molecular Quantum-dot Cellular Automata produce a highly non-linear characteristic that can be used to get something like logic gates with a very low power dissipation and very high device densities.

  20. Clocked Molecular Quantum-dot Cellular Automata • L Conclusion: There is too much work to do to design a good real device that can operate at room temperature and can resist to the imperfections occurring in the industrial process for large scale diffusion.

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