NanocomputersNanocomputersPatrick KennedyPatrick Kennedy

John MaleyJohn Maley

Sandeep SekhonSandeep Sekhon

HistoryHistory

Since Feynam’s “There is Plenty of Room Since Feynam’s “There is Plenty of Room at the Bottom”, nanotechnology has at the Bottom”, nanotechnology has become a hot topic.become a hot topic.

With computers being an integral part in With computers being an integral part in today’s society, nanocomputers are the today’s society, nanocomputers are the easiest and most likely route in which easiest and most likely route in which computer development may continue. computer development may continue.

Moore’s LawMoore’s Law

According to Moore’s Law, the number of According to Moore’s Law, the number of transistors that will fit on a silicon chip transistors that will fit on a silicon chip doubles every eighteen months. doubles every eighteen months. Presently, microprocessors have more than Presently, microprocessors have more than

forty million transistors; by 2010 they could forty million transistors; by 2010 they could have up to five billion. have up to five billion.

By the year 2020, the trend line of Moore’s By the year 2020, the trend line of Moore’s law states that there should be a one law states that there should be a one nanometer feature size. nanometer feature size.

TransistorsTransistors

The transistor is the most important component The transistor is the most important component of a computer today.of a computer today. More transistors = larger computer memories and More transistors = larger computer memories and

more powerful computersmore powerful computers

What is a nanocomputer?What is a nanocomputer?

The general definition of a nanocomputer The general definition of a nanocomputer is a computer which either uses nanoscale is a computer which either uses nanoscale elements in its design, or is of a total size elements in its design, or is of a total size measured in nanometers.measured in nanometers.

Types of nanocomputersTypes of nanocomputers

ElectronicElectronic

MechanicalMechanical

ChemicalChemical

QuantumQuantum

Electrical NanocomputersElectrical Nanocomputers

Electronic nanocomputers would operate Electronic nanocomputers would operate in a manner similar to the way present-day in a manner similar to the way present-day microcomputers work. microcomputers work.

Due to our fifty years of experience with Due to our fifty years of experience with electronic computing devices, advances in electronic computing devices, advances in nanocomputing technology are likely to nanocomputing technology are likely to come in this direction. come in this direction. 

How it worksHow it works

Although electronic nanocomputers will not use Although electronic nanocomputers will not use the traditional concept of transistors for its the traditional concept of transistors for its components, they will still operate by storing components, they will still operate by storing information in the positions of electrons.  information in the positions of electrons. 

There are several methods of nanoelectronic There are several methods of nanoelectronic data storage currently being researched.  data storage currently being researched.  Among the most promising are single electron Among the most promising are single electron transistors and quantum dots.transistors and quantum dots.

All of these devices function based upon the All of these devices function based upon the principles of quantum mechanics. principles of quantum mechanics.

Transistor replacementsTransistor replacements

Resonant Tunneling TransistorResonant Tunneling Transistor Single Electron TransistorSingle Electron Transistor Quantum Dot CellQuantum Dot Cell Molecular Shuttle SwitchMolecular Shuttle Switch Atom RelayAtom Relay Refined Molecular RelayRefined Molecular Relay

Single Electron TransistorsSingle Electron Transistors

The single electron transistor (SET) is a new The single electron transistor (SET) is a new type of switching device that uses controlled type of switching device that uses controlled electron tunneling to amplify currentelectron tunneling to amplify current

SETSET

When the gate voltage is set to zero, very little tunneling When the gate voltage is set to zero, very little tunneling occurs.occurs.

The charge transfer is continuous.The charge transfer is continuous. This voltage controlled current behavior makes the SET This voltage controlled current behavior makes the SET

act like a field effect transistor, just on a smaller scale.act like a field effect transistor, just on a smaller scale.

Resonant Tunneling DeviceResonant Tunneling Device

RTD’s are constructed from semiconductors RTD’s are constructed from semiconductors hetero-structure made from pairs of different hetero-structure made from pairs of different alloys III-IV alloys.alloys III-IV alloys.

Quantum DotsQuantum Dots

They are nanometer scaled “boxes” for They are nanometer scaled “boxes” for selectively holding or releasing electrons.selectively holding or releasing electrons.

The number of electrons can be changed The number of electrons can be changed by adjusting electric fields in the area of by adjusting electric fields in the area of the dot.the dot.

Dots range from 30nm to 1 micron in size Dots range from 30nm to 1 micron in size and hold anywhere from 0 to 100s of and hold anywhere from 0 to 100s of electrons.electrons.

Quantum Dot CellQuantum Dot Cell

Logic gates can be created using dot cells.Logic gates can be created using dot cells.

Molecular Shuttle SwitchMolecular Shuttle Switch

The shuttle is a ring shaped molecule the encircles and The shuttle is a ring shaped molecule the encircles and slides along a shaft-like chain molecule.slides along a shaft-like chain molecule.

The shaft also contains a biphenol and a benzidine The shaft also contains a biphenol and a benzidine group which serve as natural stations between which the group which serve as natural stations between which the shuttle moves.shuttle moves.

Atom RelayAtom Relay

It consists of a carefully patterned line of atoms It consists of a carefully patterned line of atoms on a substrate.on a substrate.

Consists of two atom wires connected by a Consists of two atom wires connected by a mobile switching atom.mobile switching atom.

Refined Molecular RelayRefined Molecular Relay

Based on atom movement.Based on atom movement. Rotation of molecular group affects the electric Rotation of molecular group affects the electric

current.current.

ComparisonComparison

Mechanical NanocomputersMechanical Nanocomputers

Mechanical nanocomputers would use tiny Mechanical nanocomputers would use tiny moving components called nanogears to moving components called nanogears to encode information. encode information.

Other than being scaled down in size Other than being scaled down in size greatly, the mechanical nanocomputer greatly, the mechanical nanocomputer would operate similar to the mechanical would operate similar to the mechanical calculators used during the 1940s to calculators used during the 1940s to 1970s. 1970s.

Mechanical NanocomputersMechanical Nanocomputers

Eric Drexler and Ralph Merkle are the Eric Drexler and Ralph Merkle are the leading nanotech pioneers involved with leading nanotech pioneers involved with mechanical nanocomputers.mechanical nanocomputers.

They believe that through a process They believe that through a process known as mechanosynthesis, or known as mechanosynthesis, or mechanical positioning, that these tiny mechanical positioning, that these tiny machines would be able to be assembled. machines would be able to be assembled.

How it worksHow it works

In today’s conventional microelectronics, In today’s conventional microelectronics, voltages of conducting paths represent digital voltages of conducting paths represent digital signals, and logic gates used as transistors. signals, and logic gates used as transistors. For the mechanical nanocomputer, the displacement For the mechanical nanocomputer, the displacement

of solid rods would represent the digital signal. of solid rods would represent the digital signal. Rod logic would enable, “the implementation of Rod logic would enable, “the implementation of

registers, RAM, programmable logic arrays, mass registers, RAM, programmable logic arrays, mass storage systems and finite state machinesstorage systems and finite state machines

NanosystemsNanosystems

Drexler declared that the nanocomputer could Drexler declared that the nanocomputer could contain about, 106 transistor like interlocks contain about, 106 transistor like interlocks within a 400nm cube, have clock speeds of within a 400nm cube, have clock speeds of about 1 GHz with an execution time of about about 1 GHz with an execution time of about 1000 MIPS; all with only about 60nW of power 1000 MIPS; all with only about 60nW of power consumption.consumption.

Ralph Merkle stated that, “In the future we'll Ralph Merkle stated that, “In the future we'll pack more computing power into a sugar cube pack more computing power into a sugar cube than the sum total of all the computer power that than the sum total of all the computer power that exists in the world today.”exists in the world today.”

Problems!Problems!

Slow process that would be required to Slow process that would be required to assemble the computers. assemble the computers. Hand made parts would have to be Hand made parts would have to be

assembled one atom at a time by an STM assembled one atom at a time by an STM microscope. microscope.

Due to this slow and tedious process, Due to this slow and tedious process, researchers also believe that reliability of the researchers also believe that reliability of the parts would suffer. parts would suffer.

Quantum NanocomputerQuantum Nanocomputer

The basis for the idea of a quantum The basis for the idea of a quantum nanocomputer came from the work of Paul nanocomputer came from the work of Paul Benioff and Richard Feynam during the Benioff and Richard Feynam during the 1980s. 1980s.

How it worksHow it works

The quantum nanocomputers are planned The quantum nanocomputers are planned to hold each bit of data as a quantum state to hold each bit of data as a quantum state of the computerof the computer

By means of quantum mechanics, waves By means of quantum mechanics, waves would store the state of each nanoscale would store the state of each nanoscale component. component. Information would be stored as the spin Information would be stored as the spin

orientation or state of an atom. orientation or state of an atom.

How it works How it works

With the correct setup, constructive With the correct setup, constructive interference would emphasize the wave interference would emphasize the wave patterns that held the right answer, while patterns that held the right answer, while destructive interference would prevent any destructive interference would prevent any wrong answers. wrong answers.

Problems with Quantum computersProblems with Quantum computers

The main problem with this technology is The main problem with this technology is instability. Instantaneous electron energy instability. Instantaneous electron energy states are difficult to predict and even states are difficult to predict and even more difficult to control. more difficult to control. An electron can easily fall to a lower energy An electron can easily fall to a lower energy

state, emitting a photonstate, emitting a photon A photon striking an atom can cause one of A photon striking an atom can cause one of

its electrons to jump to a higher energy state. its electrons to jump to a higher energy state.

Chemical NanocomputersChemical Nanocomputers

Also known as biochemical nanocomputers, they Also known as biochemical nanocomputers, they would store and process information in terms of would store and process information in terms of chemical structures and interactions. chemical structures and interactions. The development of a chemical nanocomputer will The development of a chemical nanocomputer will

likely proceed along lines similar to genetic likely proceed along lines similar to genetic engineering. engineering.

Engineers must figure out how to get individual atoms Engineers must figure out how to get individual atoms and molecules to perform controllable calculations and molecules to perform controllable calculations and data storage tasks and data storage tasks

AdvancesAdvances

In 1994, Leonard Adelman took a giant In 1994, Leonard Adelman took a giant step towards a different kind of chemical step towards a different kind of chemical or artificial biochemical computer.or artificial biochemical computer.

He used fragments of DNA to compute He used fragments of DNA to compute the solution to a complex graph theory the solution to a complex graph theory graph. graph.

Adelman’s methodsAdelman’s methods

Adleman's method utilized sequences of DNA's Adleman's method utilized sequences of DNA's molecular subunits to represent vertices of a molecular subunits to represent vertices of a network or "graph". network or "graph".

Combinations of these sequences formed Combinations of these sequences formed randomly by the massively parallel action of randomly by the massively parallel action of biochemical reactions in test tubes described biochemical reactions in test tubes described random paths through the graph. random paths through the graph.

Adleman was able to extract the correct answer Adleman was able to extract the correct answer to the graph theory problem out of the many to the graph theory problem out of the many random paths represented by the product DNA random paths represented by the product DNA strands.strands.

ProblemsProblems

These systems are largely uncontrollable These systems are largely uncontrollable by humans. by humans.

Limited problem domain, lacking efficient Limited problem domain, lacking efficient input and output techniques. input and output techniques.

Big problemsBig problems

Though each nanocomputer has its own Though each nanocomputer has its own set of problems, each share some set of problems, each share some common problems.common problems. A way must be found to manufacture A way must be found to manufacture

components on the scale of a single components on the scale of a single molecule. molecule.

How to actually constructing a nanoelectric How to actually constructing a nanoelectric device.device.

The Interconnect ProblemThe Interconnect Problem

Perhaps the greatest problem is Perhaps the greatest problem is something termed the "Interconnect something termed the "Interconnect Problem." Problem."

Basically, it's the question of how to Basically, it's the question of how to interface with the nanocomputer.interface with the nanocomputer. With such a dense computational structure, With such a dense computational structure,

how does one get information in or out? how does one get information in or out? There so many separate elements that there There so many separate elements that there

would have to be a multitude of connections would have to be a multitude of connections within the computer itself. within the computer itself.

Future of nanocomputersFuture of nanocomputers Nanotechnology has huge potential in building smaller Nanotechnology has huge potential in building smaller

and smaller computers. and smaller computers. Far greater amounts of information would be stored in Far greater amounts of information would be stored in

the same amount of space. This has enormous space-the same amount of space. This has enormous space-saving implications. saving implications.

Someday, all the books in the world could fit into the Someday, all the books in the world could fit into the space of a square inch. Such efficient data storage has space of a square inch. Such efficient data storage has great potential for business and scientific research in all great potential for business and scientific research in all fields. fields.

Such microcomputers also have great potential for the Such microcomputers also have great potential for the entertainment industry. With such great data storage entertainment industry. With such great data storage capacity, extremely elaborate computer games and capacity, extremely elaborate computer games and virtual reality environments could be created. virtual reality environments could be created.

ResourcesResources 1. 1. http://http://www.mitre.org/tech/nanotech/futurenano.htmlwww.mitre.org/tech/nanotech/futurenano.html

2. http://whatis.techtarget.com/definition/0,,sid9_gci514014,00.html2. http://whatis.techtarget.com/definition/0,,sid9_gci514014,00.html

3.http://searcht.aimhome.netscape.com/aim/boomframe.jsp?3.http://searcht.aimhome.netscape.com/aim/boomframe.jsp?query=mechanical+nanocomputers&page=2&offset=0&result_url=redirquery=mechanical+nanocomputers&page=2&offset=0&result_url=redir%3Fsrc%3Dwebsearch%26requestId%3Fsrc%3Dwebsearch%26requestId%3D7eb7002b08196fa7%26clickedItemRank%3D18%26userQuery%3D7eb7002b08196fa7%26clickedItemRank%3D18%26userQuery%3Dmechanical%2Bnanocomputers%26clickedItemURN%3Dhttp%253A%3Dmechanical%2Bnanocomputers%26clickedItemURN%3Dhttp%253A%252F%252Fwww.rootburn.com%252Fportfolio%252Fnano%252F%252F%252Fwww.rootburn.com%252Fportfolio%252Fnano%252F%26invocationType%3Dnext%26fromPage%3DAIMNextPrev%26amp%26invocationType%3Dnext%26fromPage%3DAIMNextPrev%26amp%3BampTest%3D1&remove_url=http%3A%2F%2Fwww.rootburn.com%3BampTest%3D1&remove_url=http%3A%2F%2Fwww.rootburn.com%2Fportfolio%2Fnano%2F%2Fportfolio%2Fnano%2F

4. http://washingtontimes.com/upi-breaking/20050317-124226-2271r.htm 4. http://washingtontimes.com/upi-breaking/20050317-124226-2271r.htm

5. A. Aviram, M. Ratner, “Molecular Rectifiers” Chem.phys letter Vol. 29. 5. A. Aviram, M. Ratner, “Molecular Rectifiers” Chem.phys letter Vol. 29. pgs 277-283pgs 277-283

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