SEMINAR ON SEMINAR ON MOLECULAR ELECTRONICS
Nov 19, 2014
SEMINAR ONSEMINAR ON
MOLECULAR ELECTRONICS
What is MoletronicsWhat is Moletronics
• It is interdisciplinary theme that spans Physics , Chemistry & Material science.
• Special feature is the use of molecular building block for fabrication of electronic component in both active and passive form.
• It is such field of nanoscience ,that evolves with the exploration of the electronic level structure , response & transport for development of electronic devices.
• As there is binding of molecular building block it forms larger structure and show dynamical stereochemistry.
History• Robert muliken & Albert Szent-Gyorgi proposed
study of charge transfer theory in1940.• In 1974 Mark Ratner & Avi Aviram illustrated a
theoratical molecular rectifier.• Later Avi Aviram detailed a single molecular field
effect transistor in1988.• In 2000Shirakawa, Heeger and MacDiarmid won
Noble prize in physics for potentially high conductivity of (oxidised) polyacetelene & it’subsequent development.
About Molecular ElectronicsAbout Molecular Electronics
• The principle of above research is that biological systems can give useful paradigm for developing electronic and computational devices at the molecular level.
• The approach involves the design and synthesis of dyads, triads and other super molecular species using the techniques of organic chemistry.
• In order to studied newly prepared molecule time resolved laser spectroscopy, NMR spectroscopy.
Why molecular electronicsWhy molecular electronics
• For electronic application, molecular structures has four major advantages:
• Size.
• Assembly & Recognition.
• Dynamical stereochemistry.
• Synthetic tailor ability.
FigureFigureBuckminister Fullerene
Rotating view of Buckminister Fullerene C60 crystal
Moore’s lawMoore’s law• The number of transistors that can be fabricated
on a silicon integrated circuit--and therefore the computing speed of such a circuit--is doubling every 18 to 24 months.
• After four decades, solid-state microelectronics has advanced to the point at which 100 million transistors, with feature size measuring 180 nm can be put onto a few square centimeters of silicon.
Electrode effectElectrode effect• The molecule electrode interface limit current
flow & completely modify the measured electrical response of the junction.
• Poor covalent bonding exists between molecule and electrode.
• A related consideration involves how chemical nature of molecule-electrode affects the rest of the molcule
Molecule Electronics Molecule Electronics CircuitsCircuits
• The proposed circuit architectures have attempted to deal with five key issues:
• Tolerance to manufacturing defects.• Introduction to non-traditional fabrication
methods.• scalability to near molecular dimensions.• Briding between device densities.• Fabrication symplicity.
Some Molecular Electronics Some Molecular Electronics CircuitCircuit
FEDs SETs
Crossbars & DemultiplexersCrossbars & Demultiplexers
• The most attractive architectures for designing molecular-electronics circuits for computational applications and interfacing them to the macroscopic world is the crossbar.
• The memory, shown on the right, consists of two major components. The central crossbar—the crossing of16 vertical and 16 horizontal black wires—constitutes a 256-bit memory circuit.
Figure of Crossbars and Figure of Crossbars and DemultiplexersDemultiplexers
Crossbars and Demultiplexers
AdvantagesAdvantages• Tiny.
• Low power consumption.
• Able to integrate large circuit
• Re-configurable.
DisadvantagesDisadvantages
• Controlled fabrication with in specified tolerances.
• Hard experimental verification.
ApplicationApplication• Sensors.
• Displays, Energy transduction devices.
• Smart Material, Molecular scale transistors.
• Molecular Motors, Logic and memory devices.
ConclusionConclusion• Molecular systems, or systems based on small
organic molecules, possess interesting and useful electronic properties.
• The investigations of molecular systems that have been performed in the past have been strongly influenced.
• The potential application of molecular electronics has already attracted the interest of some large corporate.