Transcript Tools to Make Nanostructures “the challenge to Moore’s Law

Tools to Make Nanostructures
“the challenge to Moore’s Law“
 Scanning Probe Instruments
 Lithography
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


Nanoscale
Dip Pen
E-Beam
Nanosphere Liftoff
Molecular Synthesis
Self Assembly
Nanoscale Crystal Growth
Polymerization
Nanobricks
NanoCAD
The Return of Scanning Probe
Instruments
Assembling materials
atom-by- atom or
molecule-by-molecule
 Analogy – “bulldozer”
or “crane” or
“backhoe”
 Elegant but slow and
expensive
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
http://www.aip.org/mgr/png/html/abacus.htm
•A series of STM images showing the numbers 0 through 10
•represented by single carbon-60 molecules (buckyballs) on a
•copper surface. The top row shows zero, with no molecules at
•the end of the row, and the successive rows provide representations
•of the numbers 1-10, with the appropriate numbers of molecules at
•the end of each row.
(Image courtesy IBM Zurich Research Laboratory.)
Nanoscale Lithography

“silk screen or rubber
stamp concept”
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Micro-imprint lithography
developed by George
Whitesides (Harvard)
-
Pattern inscribed onto a
rubber surface
(silicon/oxygen polymer) and
the rubber surface is coated
with molecular ink
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Complex but inexpensive
and can make numerous
copies
Figure 15. Two examples of imprinting over a
planarized surface.
http://www.molecularimprints.com/NewsEvents/tech_articles/new
_articles/MOT_SPIE2003_Imprint_Lith_review_paper.pdf
Dip Pen Lithography
“fountain pen analogy”
 Developed by Chad Mirkin
at Northwestern Univ.
 AFM tips are ideal
nanopens
 Almost anything can be
used as nanoink
 almost any surface can
be written on
 Almost anystructure can
http://chemgroups.northwestern.edu/mirkingroup/dpn.htm
be made no matter how
detailed or complex
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Dip-Pen Nanolithography: Transport of molecules to
the surface via water meniscus.
A)
Ultra-high resolution pattern of mercaptohexadecanoic acid on atomically-flat gold
surface. B) DPN generated multi-component nanostructure with two aligned
alkanethiol patterns. C) Richard Feynmann's historic speech written using the DPN
nanoplotter
E-Beam Lithography

Use of electron
beam to make
structures at
nanoscale

Applications in
microelectronics
Figure 4.4. Two electrodes made using
E-beam lithography. Thelight horizontal
structure is a carbon nanotube.
Courtesy of the Dekker Group, Delft Institute of Technology.

http://brainsturbator.com/pdf/Prentice%20Hall%20Ptr%20%
20Nanotechnology%20A%20Gentle%20Introduction%20To%
20The%20Next%20Big%20Idea.pdf
Nanosphere Liftoff Lithography
Figure 4.5. Schematic of the nanosphere liftoff lithography process.
Courtesy of the Van Duyne Group, Northwestern University.
http://brainsturbator.com/pdf/Prentice%20Hall%20Ptr%20%20Nanotechnology%20A%20Gentle%20Introduction%20To%20The%20Next%20Big%20Idea.pdf
Molecular Synthesis
- making specific molecules for specific purposes
- drug delivery techniques
- extensive molecular synthetic work in drug companies (e.g.
Lipitor, Penicillin, Taxol, Viagra)
http://www.sigmaaldrich.com/img/assets/3760/Acta_37_2.pdf
Self Assembly
Making nanostructures by
letting the molecules sort
themselves out
 Molecules will always seek
the lowest energy available
to them
 Molecules will align
themselves into particular
positions
 Use for large nanoscale
arrays, different length
scales, low cost, generality
 Electronic applications,
coatings
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http://brainsturbator.com/pdf/Prentice%20Hall%20Ptr%20%20Nanotechnology%20A%20Gentle%20Introduction%20To%20The%2
0Next%20Big%20Idea.pdf
Figure 4.6. Molecular model (top) of a self-assembled
"mushroom" (more correctly a rodcoil polymer). The
photograph (bottom) shows control of surface wetting by a
layer of these mushrooms.
Courtesy of the Stupp Group, Northwestern University.
Nanoscale Crystal Growth
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“seed crystal concept”
Silicon Boules
Manipulating seed
crystals to grow to
unusual shapes
 Charles Lieber
(Harvard)
Figure 4.7. Two parallel nanowires. The light color is silicon,
and the darker color is silicon/germanium.
Courtesy of Yang Group, University of California at Berkeley.

http://brainsturbator.com/pdf/Prentice%20Hall%20Ptr%20%20Nanotechnology%20A%20Gentle%20Introduction%20To%2
0The%20Next%20Big%20Idea.pdf
Polymerization
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Controlled polymerization, in
which one monomer at a time
is added to the next, is very
important for specific elegant
structures.
Robert Letsinger and his
students at Northwestern
University have developed a
series of methods for
preparing specific short DNA
fragments. These are called
oligonucleotides.

The so-called gene machines
use elegant reaction chemistry
to construct specific DNA
sequences.
Figure 4.8. Schematic of the DNA hybridization process. The
"matched" side shows how a DNA strand correctly binds to its
complement and the "mismatched" side shows how errors can
prevent binding.
Courtesy of the Mirkin Group, Northwestern University.