Motion in One Dimension

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TAMU, 02/01/08
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Nanotechnology Vision and Implementation

• Winfried Teizer
• Center for Nanoscale
• Science and Technology
• and
• Department of Physics
• Texas AM University

TAMU, 02/01/08
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Nanotechnology At the Beginning

• I imagine experimental physicists must often
  look with envy at men like Kamerlingh Onnes, who
  discovered a field like low temperature, which
  seems to be bottomless and in which one can go
  down and down. Such a man is then a leader and
  has some temporary monopoly in a scientific
  adventure. Percy Bridgman, in designing a way to
  obtain higher pressures, opened up another new
  field and was able to move into it and to lead us
  all along. The development of ever higher vacuum
  was a continuing development of the same kind.
• I would like to describe a field, in which
  little has been done, but in which an enormous
  amount can be done in principle. This field is
  not quite the same as the others in that it will
  not tell us much of fundamental physics (in the
  sense of, What are the strange particles?'')
  but it is more like solid-state physics in the
  sense that it might tell us much of great
  interest about the strange phenomena that occur
  in complex situations. Furthermore, a point that
  is most important is that it would have an
  enormous number of technical applications.
• What I want to talk about is the problem of
  manipulating and controlling things on a small
  scale.

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Who Invented Nanotechnology?

• 1959 Richard Feynman (Nobel in Physics)
• Theres Plenty of Room at the Bottom An
  invitation to enter a new field of physics.
• Offered two 1,000 prizes to build an electric
  motor in a 1/64 inch cube another to reduce a
  page of a book to an area 1/25,000 smaller, and
  read it using an electron microscope
• 1960 the first prize claimed
• 1985 a graduate student claimed the second by
  writing a page from A Tale of Two Cities on a
  page 1/160 of a milimeter in length, using
  electron beam lithography.

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Outline

• What is Nanotechnology?
• What can Nanotechnology do for us now?
• What may Nanotechnology be able to do in the
  future?
• Should we go down this path?

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A Wake-up Call

• Invention of scanning tunneling and atomic force
  microscope, (Gerd Binning and Heinrich Rohrer of
  IBM, Nobel in Physics, 1986)

Xe atoms on very cold nickel Why Xe? Why cold?
AFM Tip. The smallest tips are 1 atomic diameter
http//idol.union.edu/malekis/ESC24/Philips
Pages/Little Big Science_files/frame.htm
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Nanotechnology A Definition

• The study and applications of things or
  structures that are of the order or below 100 nm
  (1 nm 10-9 m or one-billionth of a meter) in
  sizes.
• Essentially this is the study of the super
  small.
• Manipulation of building blocks at this scale
• Expectation of practical applications

• Length scale comparisons
• Diameter of human hair 100 ?m 100,000 nm
• Active part of smallest silicon transistor lt 20
  nm
• Most atoms are the size of 1 Angstrom
• Nanoscale begins at or below 100 nm, i.e., 1000
  atoms end-to-end or 109 atoms/cluster in 3-D)

www.nanofab.psu.edu/education/nue workshop ppt/
Adesida Presentation.ppt
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The Nanoscale

• The principles of physics, as far as I can see,
  do not speak against the possibility of
  maneuvering things atom by atom.
• Richard Feynman, 1959

http//www.ad.tut.fi/aci/courses/7606082/Presentat
ions/Introduction_Lecture.pdf
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Outline

• What is Nanotechnology?
• What can Nanotechnology do for us now?
• What may Nanotechnology be able to do in the
  future?
• Should we go down this path?

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How to fabricate Nanostructures? 2 principal
approaches

• Bottom-Up
• Assembling structures from the atomic/molecular
  level
• Novel approach, conceptually imitating nature
• E.g. chemical self-assembly

• Top-Down
• Miniaturizing existing processes at the
  Macro/Microscale
• Traditional approach in industrial applications
• E.g. Lithography, backbone of computing systems

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Lithography

• Lithography in Art
• How lithography works
• Materials used for lithography drawing
• Photolithography
• Photolithographic process

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Lithography in Art

• Invented by Alois Senefelder in 1798
• Used for book illustrations, artist's prints,
  packaging, posters etc.
• In 1825, Goya produced a series of lithographs.
• In the 20th and 21st century, become an important
  technique with unique expressive capabilities in
  the Art field

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How Lithography started

• Lithography (Greek for "stone drawing") relies on
  the fact that water and grease repel
• Draw a pattern onto a flat stone surface with a
  greasy substance
• Paint the printing ink onto the stone
• While the stone background absorbs water, the
  greasy substance retains wet ink on top
• Press paper against the stone to transfer the
  pattern
• Positive! Repeatable!

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Materials used for lithography drawing

• Litho crayons and pencils (containing wax,
  pigment, soap and shellac), conte crayons, pens
  and graphite pencils, etc.

Bulls of Bordeaux by Goya
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Lithography, to date

• Miniaturized computing circuits require mass
  manufacturing of small features ? push
  lithographic approach to new limits
• Some lithography approaches for manufacturing
• Optical lithography (including ultraviolet)
• X-Ray lithography
• Electron Beam lithography
• Ion Beam lithography
• Dip-Pen lithography

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Optical/UV Lithography

• Workhorse of current chip manufacturing processes
• Limited by wave length of light employed
• Smaller features ? reduce wave length ? UV light
• Here is how it works

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Photolithographic process

• Wafer cleaning
• Barrier layer formation
• Photoresist application
• Soft baking
• Mask alignment
• Exposure and development
• Hard-baking

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Optical Lithography
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Optical Lithography
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Optical Lithography
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Optical Lithography
Lift-Off
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Fundamental Limitations

• Smallest Feature Size is limited by
• wave length of light used
• Currently deep UV light is used to produce
• sub-?m line widths
• Use electrons to write even smaller structures

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Example Pentium III
Low Mag High Mag
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History of transistor

• Discovered and Invented at Bell Labs in 1947
• By John Bardeen, Walter Brattain, and William
  Shockley
• Practical and useful electronic devices for
  communications

First transistor

• (1st_transistor.jpg)http//www.101science.com/tra
  nsistor.htm

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Outline

• What is Nanotechnology?
• What can Nanotechnology do for us now?
• What may Nanotechnology be able to do in the
  future?
• Should we go down this path?

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Bottom-Up Techniques

• Bottom-Up implies the construction of larger
  systems from more basic building blocks
• Many natural systems are organized this way, e.g.
  biological systems
• Multi layer hierarchical approaches are
  attracting most attention, e.g. molecules, cells,
  functional elements
• In most stringent definition, the bottom up
  approach starts at the molecular level, that is
  certainly most useful

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A vision Portability

• Important aspect of bottom up
• You can (1) extract information about an object
  on the nanoscale, (2) ship information and (3)
  reassemble the object in a different location
• Star Trek beaming
• But Contract Small Pox by email

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Self Assembled Monolayers

• Benefits
• Can pattern materials which dont allow
  lithographic approach
• Can utilize an approach with further miniaturizes
  structures

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Self Assembled Monolayers

• Thiol adsorption to gold within seconds
• Assembly requires more time, diffusion,
  reorganization

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Self Assembled Monolayers

• Creating gradients
• Want to have a gradual change in composition of a
  film across a surface
• Use CH3(CH2)11SH and OH(CH2)11SH

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Fullerenes

• Material made of pure carbon
• Because of their molecular simplicity these
  materials may be among the strongest materials
  that are possible

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Carbon nanotubes, a few properties

• Electrical Conductivity of Copper or Silicon.
• Thermal Conductivity of Diamond.
• The Chemistry of Carbon.
• The size and perfection of DNA.

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Nanotube Bundles
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Space Elevator
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MEMS (MICRO-ELECTRO MECHANICAL SYSTEMS)

• MEMS have made electrically-driven motors smaller
  than the diameter of a human hair
• MEMS technology is NOT just about size
• Not about making things out of silicon...

http//www.mems-exchange.org
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How small is a micrometer?

• 1 ?m 10-6 meters 1000 nm
• Average diameter of a human hair 70 micrometer
• Component of MEMS may be
• lt1 ?m

http//www.vs.afrl.af.mil/Factsheets/mems.html/mem
s2.gif
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More Images of MEMS

• Courtesy Sandia National Laboratories, SUMMiTTM
  Technologies, www.mems.sandia.gov

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What are MEMS?

• Micro-Electro-Mechanical Systems
• Integration of- mechanical elements- sensors-
  actuators- electronics
• Created on a common silicon substrate
• Using Microfabrication technology

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Electronics vs. Micromechanical components

• Electronics - fabricated using integrated
  circuit (IC) process sequences
• Micromechanical components - fabricated using
  compatible "micromachining" processes

http//www.memsnet.org/mems/mems-image-1.jpeg
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Typical MEMS Applications

• Biotechnology - Scanning Tunneling Microscopes
  (STMs) to detect hazardous chemical and
  biological agents
• Communications using RF-MEMS technology -
  Improvement on electrical components (inductors,
  tunable capacitors, etc.) - Huge potential in
  various microwave circuits with mechanical switch
• Accelerometers- Better accelerometers for crash
  air-bag systems

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Advantages of MEMS Manufacturing

• Extremely diverse technology - significant effect
  on commercial and military product, e.g. flaps
• Already used for in-dwelling blood pressure
  monitoring, active suspension systems for
  automobiles, etc.
• Blurs the distinction between complex mechanical
  systems and integrated circuit electronics
• Complex electromechanical systems to be
  manufactured using batch fabrication techniques,
  increasing the reliability of the sensors and
  actuators to equal that of integrated circuits
• Cost is predicted to be much lower than
  macrodevices

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Current Challenges

• In most companies- Limited options for
  prototyping/manufacturing devices- No
  capability/expertise in microfabrication
  technology - High cost for own fabrication
  facilities

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Outline

• What is Nanotechnology?
• What can Nanotechnology do for us now?
• What may Nanotechnology be able to do in the
  future?
• Should we go down this path?

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Ethical Consideration
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Nanoscale in Nature

• Nanoscale structures in nature Diatoms (single
  cell algae)
• Diatoms have a silica (glass) structure cell wall.

http//www.tamu.edu/mic/instruments.htmljsm-6400
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Conclusions

• Nanotechnology can be fun (!) and useful (!?)
• If nanotechnology will fulfill the promise, there
  will be a lot of new gadgets and jobs, many of
  which are unheard of
• Like many things in science, one needs to watch
  for the drawbacks, but there is no reason to panic

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References
http//www2.mmlc.nwu.edu/c303/levavy/lith1.html
http//www.ece.gatech.edu/research/labs/vc/theory/
photolith.html
http//en.wikipedia.org/wiki/Photolithography
http//britneyspears.ac/physics/fabrication/photol
ithography.htm
http//www.101science.com/transistor.htm
http//www.lucent.com/minds/transistor
http//www.apsidium.com/elements/032.htm
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References

• Referenceshttp//www.memsnet.org/mems/what-is.ht
  mlhttp//www1.coe.neu.edu/pmakaram/mems.htm
• http//www.mems-exchange.org
• http//mems.sandia.gov/scripts/images.asp

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Sources
http//www.nano.org.uk/nano.htm http//cnst.rice.e
du/ http//www.surface.mat.ethz.ch/ http//www.ifm
.liu.se/Applphys/ftir/sams.html http//en.wikipedi
a.org/wiki/Space_elevator