21-02-2010, 11:50 AM
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MOLECULAR ELECTRONICS
IC TECHNOLOGY
Main frame computers “ Desktop computers “ Laptop computers
SSI(small scale integration)
MSI(medium scale integration)
LSI(large scale integration)
ULSI(ultra large scale integration)
Limitations of IC technology
Beyond ULSI Moorâ„¢s law fails
Physical limitations
Economical issues
INTRODUCTION
Emerged in the 1980â„¢s
Prof. FOREST CARTER(U.S.A)
Replacing IC technology
Molecule instead of transistor
WHY MOLECULAR ELCTRONICS
LOW-COST DEVICES (OLED , Chemical sensors)
Beyond the MOORâ„¢S LAW: more devices per unit area and not only
Self-assembly: new old way to assemble complicated devices
Complex (designer) logic functions
Interacting with living organisms:
HISTORY
Organic materials in displays of watches and calculators
Material scientists started working on organic solids as alternative semiconductors because of their attractive Optical properties.
Research started in Soviet Union ,Japan ,U.K , France , Germany and U.S.A
Prof. Forest Carter conducted in 1980â„¢s a number of international conferences on the subject mainly initiated the interest in molecular electronics as a separate and special subject
Coordination of diverse fields like:
1. Computer,
2. Electronics,
3. Physics,
4. Chemistry,
5. Biology,
6. Material science etc.
Molecular electronics is a technological challenge to explore the possible applications of organic materials ,
non-linear optics and biologically important materials in the field of electronics
Conductive organic molecules
Plastic can indeed, under certain circumstances, be made to behave very like a metal - a discovery for which Alan J. Heeger , Alan G. MacDiarmid and Hideki Shirakawa are to receive the Nobel Prize in Chemistry 2000.
Molecular Electronics
Molecular electronics is a platform technology
Size, cost, fundamental comparisons
Self-assembly, bottom-up vs. top-down
Switching (~1 billion) and memory (hours) demo
Functionalization of nanotubes
Nanocell Computing
Commercial benefits: Lower production costs, power consumption and size. Enhanced density and functionality
Commercial evolution: (a) replacement of cost limiting components via hybrids, (b) electronics everywhere, © nanocell computing (d)¦
Limits of top-down fabrication
¢Close to the limit of miniaturization : hindered by laws of physics and high cost.
¢Little room left for novel architecture, new concept for nonlinear devices and memories.
Possibility of bottom-up approach
¢Chemical engineering of organic molecules with their physical and electronic properties.
¢Bottom-up (self-assembly) fabrication that builds small structures from atoms and molecules with particular functionality.
¢Expected to bring a new dimension in design flexibility.
¢Chemical synthesis has advantage in mass production and low cost.
Self-assembly is a process to lower the surface free energy,
so the process tends to eliminate foreign or faulty structures of molecules
Error correcting process
Technically attractive and cost effective
Needs self-assembly strategy that enables easy formation of complex patterns to program the useful structures and electronic properties in nanoscale.
Polyphenylene-Based chains
¢ Polyphenylene based molecular wires and switches use chains of organic aromatic benzene rings.
¢ An individual benzene ring less one of its hydrogens,giving the phenyl group C6H5
¢ Polyphenylenes are obtained by binding phenylenes to each other on both sides and ending the chain-like structures with phenyl groups.
¢ HOMO: highest occupied molecular orbital (similar to valence band in solid-state)
¢ LUMO: lowest unoccupied molecular orbital (similar to conduction band)
¢ Energy gap : difference between HOMO and LUMO
¢ Conductance can change in accordance with molecular shape (because of different electronic properties).
CARBON NANOTUBES
Also known as bucky tube.
Used on micropatted semiconductor surfaces make a very conductive wire.
Conductive properties ranging from excellent conduction to pretty good insulation.
WORKING
In Digital electronics , ËœYESâ„¢ and ËœNOâ„¢ states are usually and respectively implemented and defined by ËœONâ„¢ and ËœOFFâ„¢ conditions of a switching transistor . Prof. Carter postulated that instead using a transistor , a molecule (a single molecule or a small aggregate of molecule) might be used to represent the two states , namely ËœYESâ„¢ and ËœNOâ„¢ of digital electronics.
Advantages of Molecular Electronics
¢Nano-scaled structures with identical size
¢Ultra High density: 106 times denser than Si logic circuits
¢Very cheap
Critical issues on Molecular Electronics
¢Organization into high density 2-D and 3-D arrays
¢Connection in large number to input/output lines
APPLICATIONS
Plastic electronic systems.
Optical computers.
Chemical or bio-computers with inbuilt thinking functions.
Biochips.
Economic solar cells.
Optical soliton for communication.
Grain sized computers can be made.
MOLECULAR ELECTRONICS
IC TECHNOLOGY
Main frame computers “ Desktop computers “ Laptop computers
SSI(small scale integration)
MSI(medium scale integration)
LSI(large scale integration)
ULSI(ultra large scale integration)
Limitations of IC technology
Beyond ULSI Moorâ„¢s law fails
Physical limitations
Economical issues
INTRODUCTION
Emerged in the 1980â„¢s
Prof. FOREST CARTER(U.S.A)
Replacing IC technology
Molecule instead of transistor
WHY MOLECULAR ELCTRONICS
LOW-COST DEVICES (OLED , Chemical sensors)
Beyond the MOORâ„¢S LAW: more devices per unit area and not only
Self-assembly: new old way to assemble complicated devices
Complex (designer) logic functions
Interacting with living organisms:
HISTORY
Organic materials in displays of watches and calculators
Material scientists started working on organic solids as alternative semiconductors because of their attractive Optical properties.
Research started in Soviet Union ,Japan ,U.K , France , Germany and U.S.A
Prof. Forest Carter conducted in 1980â„¢s a number of international conferences on the subject mainly initiated the interest in molecular electronics as a separate and special subject
Coordination of diverse fields like:
1. Computer,
2. Electronics,
3. Physics,
4. Chemistry,
5. Biology,
6. Material science etc.
Molecular electronics is a technological challenge to explore the possible applications of organic materials ,
non-linear optics and biologically important materials in the field of electronics
Conductive organic molecules
Plastic can indeed, under certain circumstances, be made to behave very like a metal - a discovery for which Alan J. Heeger , Alan G. MacDiarmid and Hideki Shirakawa are to receive the Nobel Prize in Chemistry 2000.
Molecular Electronics
Molecular electronics is a platform technology
Size, cost, fundamental comparisons
Self-assembly, bottom-up vs. top-down
Switching (~1 billion) and memory (hours) demo
Functionalization of nanotubes
Nanocell Computing
Commercial benefits: Lower production costs, power consumption and size. Enhanced density and functionality
Commercial evolution: (a) replacement of cost limiting components via hybrids, (b) electronics everywhere, © nanocell computing (d)¦
Limits of top-down fabrication
¢Close to the limit of miniaturization : hindered by laws of physics and high cost.
¢Little room left for novel architecture, new concept for nonlinear devices and memories.
Possibility of bottom-up approach
¢Chemical engineering of organic molecules with their physical and electronic properties.
¢Bottom-up (self-assembly) fabrication that builds small structures from atoms and molecules with particular functionality.
¢Expected to bring a new dimension in design flexibility.
¢Chemical synthesis has advantage in mass production and low cost.
Self-assembly is a process to lower the surface free energy,
so the process tends to eliminate foreign or faulty structures of molecules
Error correcting process
Technically attractive and cost effective
Needs self-assembly strategy that enables easy formation of complex patterns to program the useful structures and electronic properties in nanoscale.
Polyphenylene-Based chains
¢ Polyphenylene based molecular wires and switches use chains of organic aromatic benzene rings.
¢ An individual benzene ring less one of its hydrogens,giving the phenyl group C6H5
¢ Polyphenylenes are obtained by binding phenylenes to each other on both sides and ending the chain-like structures with phenyl groups.
¢ HOMO: highest occupied molecular orbital (similar to valence band in solid-state)
¢ LUMO: lowest unoccupied molecular orbital (similar to conduction band)
¢ Energy gap : difference between HOMO and LUMO
¢ Conductance can change in accordance with molecular shape (because of different electronic properties).
CARBON NANOTUBES
Also known as bucky tube.
Used on micropatted semiconductor surfaces make a very conductive wire.
Conductive properties ranging from excellent conduction to pretty good insulation.
WORKING
In Digital electronics , ËœYESâ„¢ and ËœNOâ„¢ states are usually and respectively implemented and defined by ËœONâ„¢ and ËœOFFâ„¢ conditions of a switching transistor . Prof. Carter postulated that instead using a transistor , a molecule (a single molecule or a small aggregate of molecule) might be used to represent the two states , namely ËœYESâ„¢ and ËœNOâ„¢ of digital electronics.
Advantages of Molecular Electronics
¢Nano-scaled structures with identical size
¢Ultra High density: 106 times denser than Si logic circuits
¢Very cheap
Critical issues on Molecular Electronics
¢Organization into high density 2-D and 3-D arrays
¢Connection in large number to input/output lines
APPLICATIONS
Plastic electronic systems.
Optical computers.
Chemical or bio-computers with inbuilt thinking functions.
Biochips.
Economic solar cells.
Optical soliton for communication.
Grain sized computers can be made.
