Transcript Umangkumar Patel - Computer Science

A small, small, small world
By Ralph C. Merkle
Presented by
Umangkumar Patel
Presentation Overview
 Molecular Manufacturing
 Utility of Diamond
 Basic principles of NanoTechnology
 Why Diamond is a Dream Material?
 Chemical Vapor Deposition (CVD)
 Different types of NanoTechnology
 What will we be able to make?
 Who’s doing Nanotechnology?
 Conclusion
Molecular Manufacturing
 Manufactured products are made from the atoms.
 If we rearrange the atoms in coal (as in a pencil
lead) we can make diamond.
 If we rearrange the atoms in sand (add a few other
elements) we can make computer chips.
 If we rearrange the atoms in dirt, water, and air we
can make grass.
Molecular Manufacturing (Cont.)
 Today’s manufacturing methods are very crude at
the molecular level.
 It’s like trying to make things out of LEGO
blocks with gloves on your hand.
 Nanotechnology will let us take off the gloves.
 We will able to snap together the fundamental
building block of nature easily, inexpensively and
in an almost arrangement that we desire.
Utility of Diamond
 Often we want our products to be light and
strong.
 Depend on the number and strength of the
bonds.
 Carbon atoms can form four bounds to four
neighboring atoms.
 Strength to weight ratio of diamond is over 50
times that of steel.
Utility of Diamond (Cont.)
 We would have to modify the structure to make it
tough and shatter proof: perhaps diamond fibers.
 Diamond is also wonderful material for making
transistors and computer gates.
 Computer Gates should switch as quickly as
possible: that’s what makes computer so fast.
Utility of Diamond (Cont.)
 The gates must be made of transistors in which
the electrons move as fast as possible over the
shortest possible distance.
 Today’s computer are made of semiconductors,
and the semiconductors of choice is silicon.
 Diamond also has greater thermal conductivity,
which let’s us move heat out of diamond
transistor more quickly to prevent it from
getting too hot.
Diamond Material properties
Basic principles of NanoTechnology
 Self Assembly
 Position control
 Position device
 Stiffness
Self Assembly
 The ability of chemists to synthesize what they
want by stirring things together.
 Self assembly is a well established and powerful
method of synthesizing complex molecular
structure.
 Basic principal is stickiness
 If two molecular parts have a complimentary
shapes and charge patterns – one part has a
hollow and other part has a bump.
Self Assembly (Cont.)
 Path to Nanotechnology
 It would be hard pressed to make the very wide
range of products promised by nanotechnology.
 The parts bounce and bump into each other in all
kinds of ways.
 To make diamond, we need to use indiscriminately
sticky parts.
 These parts can’t be allowed to randomly bump
into each other.
Position Control
 Basic principal of nanotechnology
 At the microscopic scale, the idea that we hold
parts in our hands and assemble.
 Molecular scale, the idea of holding and
positioning molecules is new.
Position device
 Avoid this problem, we can hold and position the
parts.
 Molecular parts are both indiscriminately and
very sticky.
 Positional control at the molecular scale should
let us make things.
 Molecular bearings can be "run dry", as first
suggested by Feynman.
Stiffness
 Stiffness is a measure of how far something
moves when you push on it.
 SPM have been made stiff enough to image
individual atoms despite thermal noise.
 To make something that’s both small and more
stiff is challenging.
Scanning Probe Microscope
Why Diamond is a dream material?
 Used as a precious gem, heat sink, abrasive and
as wear resistant coating
 “Industrial diamond” has been synthesized
commercially for over 30 years using
HPHT techniques.
 Synthesize diamond - Chemical vapor Deposition
 Hydrocarbon gas in a excess of hydrogen
 CVD Diamond can show mechanical and
electronic properties comparable to those of
natural diamond.
CVD Process
 CVD involves a gas-phase chemical reaction
occurring above a solid surface, which causes
deposition onto that surface.
 Involves thermal or plasma activation or use of
a combustion flame.
 Temperature at 1000-1400 K.
Two types of low pressure CVD
reactor.
CVD Process (Cont.)
 Growth rates for the various deposition
process vary considerably.
 Combustion methods deposit diamond at high
rates.
 Hot filament and plasma have a much slower
growth rates but produce high quality films.
 Increasing the growth rates to economically
viable rates.
 Process is being made using microwave
deposition reactors.
CVD Diamond film

Diamond initially nucleates as
individual microcrystal, which
then grow larger until they
coalesce into a continuous film.
Here, small diamond crystals
are seen nucleating on a Ni
surface.
 Typical appearance of a
microcrystalline CVD diamond
film grown on Si. The film is
polycrystalline, with twinning
and many crystal defects
apparent.
CVD Diamond film (Cont.)
 Cross-section through a 6.7 µmthick diamond film on Si, showing
the columnar nature of the growth
up from the surface
 Nanocrystalline film, exhibiting
'cauliflower' morphology, typical of
diamond grown under high (>2%)
methane concentrations.
 This film is much smoother than the
microcrystalline film, but its
mechanical and electrical properties
are not as extreme.
Current Avenues of Molecular
Nanotechnology Research
 Wet Nanotechnology
 Dry Nanotechnology
 Computational Nanotechnology
Wet Nanotechnology
 Biological system that exist
primarily
in
a
water
environment including genetic
material, membranes, enzymes
and other cellular components.
 Like living organisms whose
form, function and evolution
are governed by the interactions
of nanometer-scale structures.
Dry Nanotechnology
 Derives from surface science and
physical chemistry.
 Fabrication of structure in carbon,
silicon, inorganic materials, metals
and semiconductors.
 Electron, magnetic and optical
devices.
Computational Nanotechnology
 The modeling and simulation of complex
nanometer – scale structures
 The predictive and analytical power of
computation
 Key players are Drexler and Merkle
What will we be able to make?
 Improved Transportation
 Atom Computers
 Military application
 Solar energy
 Environment
Improved Transportation
 Today, most airplanes are made from metal
despite the fact that diamond has a strength-toweight ratio over 50 times that of aerospace
aluminum.
 Lighter materials will make air and space travel
more economical.
Atom Computers
 Computers of the future will use atoms instead
of chips for memory.
 We’ll have more computing power in the
volume of a sugar cube than the sum total of all
the computer power that exists in the world
today
 More than 1021 bits in the same volume
Military application
 Intelligence gathering devices far too small to be
discovered
 Computerized biological/chemical weapons
 Weapons “smart” enough to kill only the
soldiers and not the innocent bystanders.
 Active defensive shields.
Solar energy
 Solar energy replace other resources.
 Power storage will become far easier and more
reliable.
Environment
 Most pollution today is a byproduct of
manufacturing, transportation, and energy
production
 MNT is atomically precise, thus zero emissions
 Impact = Population x Affluence x Technology
 MNT could be used to clean up toxic waste sites
by disassembling toxic chemicals into harmless
components
 MNT could enable a total redesign of our cities,
transportation base, energy systems, and
relationship to the environment
Who’s Doing Nanotechnology?
Conclusion
 How long before inexpensive solar cells
let us use clean solar power instead of oil,
coal, and nuclear fuel?
 How long before we can explore space at
a reasonable cost?
 How long it takes depends on what we do
and on how fast the technology evolves.
 When nanotechnology happens, we will
experience explosive change – we need to
prepare now.
References
 http://www.zyvex.com/nanotech/CDAarticle.html
 http://www.virtualschool.edu/mon/Bionomics/Nanotec
hnology.html
 http://pchem1.rice.edu/nanoinit.html
 http://www.nanozine.com
 http://www.zyvex.com/nanotech/talks/ppt
 http://www.cphoenix.best.vwh.net/nano-top.html
 http://www.bootstrap.org/colloquium/session_03_jaco
bstein.html
 http://www.coatesandjarratt.com/dsmithstp/Nanotech
nology
 http://www.actionbioscience.org/newfrontiers/merkle.html
Questions?