Quantum corral: Fe atoms on Cu(111) (r=7.3 nm)
Nanoscience is not physics, chemistry, engineering or biology.
It is all of them.
S.M. Lindsay, Introduction to Nanoscience,
Oxford University Press (2009)
Multiwalled Carbon
Nanotubes
DNA
Imaging
Dendrimers
Nanoscience is about the phenomena that occur in systems with
nanometer dimensions.
top-down
Photolitography
Microprinting
nanoclusters
0.1nm
1nm
bottom-up
Organic synthesis
Self-assembly
10nm
biomolecules
100nm
1m
10 m
Bohr radius = 0.5292Å ≈ 0.05 nm
C atom (VdW radius)=0.17 nm
In a 1nm line: 3 C atoms
In a 1nm·1nm surface: 9 C atoms
In a 1nm·1nm·1nm cube: 27 C atoms
In a 1m·1m·1m cube: 2.7·1028 C atoms
Typical nanosystems may contain from hundreds to tens of
thousands of atoms.
Graphite: 2.3·103 Kg·m-3 = 1.15·1029 C atoms·m-3
Diamond: 3.5·103 Kg·m-3 = 1.76·1029 C atoms·m-3
Nanoscience is where atomic physics converges with the physics
and chemistry of complex systems.
Quantum Mechanics
Statistical Mechanics
Quantum Mechanics dominates the world of atoms, but typical
nanosystems may contain from hundreds to tens of thousands
atoms.
Emergent behavior
How much a system is quantum mechanical?
1. Below a certain length scale (that depends on interaction
strengths) systems must be described using quantum
mechanics.
Ex. quantum dots, nanocatalysts, electronic transport through
nanowires amd thin films
2. Many processes depend on the number of available energy
states per unit energy. This quantity varies with the
dimensionality of the system.
3. The effective concentration of reactants that are confined
in nanostructures may be very high.
• 1 mole at STP occupies 22.4L, one breath is ca. 0.05 Mole N2
• Mass of earth’s atmosphere is 5 ·1018 kg (80% N2), 1 mole of
N2 weights 28 g.
• Moles N2 in atmosphere are ca. 2 ·1020
• Fraction exhaled by Caesar: 0.05/ 2 · 1020 = 2.5 · 10-22:
150 “Caesar Molecules”/mole
• In each breath we breath in: 0.05 ·150 or about 7 molecules
• 1981 Invention of Scanning Tunneling Microscopy
• G. Binning, H. Rohrer, C. Berger and E. Weibel
Surface studies by Scanning Tunneling Microscopy,
Phys. Rev. Lett. 49, 57-61 (1982)
• 1986 – First International Conference on STM
•Santiago de Compostela, Spain, 14-18 July
• 1986 – Nobel Prize to G. Binning and H. Rohrer
• 1988 – STM Imaging of DNA and biological structures
•1986 Invention of Atomic Force Microscopy
G. Binning, C.F. Quate and C. Berger
Atomic Force Microscopy, Phys. Rev. Lett. 56, 930-933 (1986)
Talk given to the American Physical Society, 1959
• “We can reverse the lens of an electron microscope in order to
demagnify as well as magnify……This, when you demagnify it
25,000x, it is still 80Å in diameter – 32 atoms across.”
Current e-beam technology
allows features as small as 10
nm to be written.
Fresnel Lens made by EBL
for focusing X-rays
(submicron patterning)
C. David, Paul Scherrer Institut
• “We would just have to press the same metal plate again
into the plastic and we would have another copy.”
Copyright (c) Stuart Lindsay 2008
PDMS Stamp technology
•
“A source of ions, sent through the lens in reverse,
could be focused to a very small spot.”
FIB = Focused Ion Beam
(Courtesy of FEI Inc.)
Molecular structure by direct imaging
• “The wavelength of an electron is only 1/20 of an Å.
So it should be possible to see the individual atoms.”
Cryo-EM reconstruction
of the Ribosome
(LeBarron et al., 2008)
20 nm
“Consider the possibility that we too can make a thing
very small, which does what we want – that we can
manufacture an object that maneuvers at that level!
…… Consider any machine – for example, an
automobile- and ask about the problems of making an
infinitesimal machine like it.”
World’s smallest motor (Zettl Lab)
(Courtesy of Professor Alex Zettl)
Making materials from atomic layers
• “So, you simply evaporate until you have a block of
stuff which has the elements…… What could we do
with layered materials with just the right layers?”
Alternate layers of HgTe and HgCdTe
T. Aoki, M. Takeguchi, P. Boieriu, R.
Singh, C. Grein, Y. Chang,
S. Sivananthan and D. J. Smith,
Microstructural characterization of
HgTe/HgCdTe superlattices
J. Cryst, Growth, 2004, 271, 29-36,
Atomic scale synthesis by “pushing atoms”
• “We can arrange atoms the way we want.”
STM deposition
(Courtesy of Prof. Wilson Ho)
Resonant antennas
for light emission and absorption
• “It is possible to emit light from a whole set of
antennas.”
O
O
O
O
O
O
Nanophotonics
O
O
O
Me2N
SO2
N
UV abs
O
O
O
N
NHO
Me2N
COOH
Br
O
NMe2
NS
O2
O
O
O
O
O
NMe2
O
O
N
O2S
O
O
O
N
Br O2S
N
NMe2
O
O
O
O
O
O
O
h
N
O2S N
O
O
N
Br
Me2N
O
Br
O
O
N SO2
N
O2
SN
O
O
E
SO2
N
O
O
O
NMe2
O
O
O
O
Photoactive
dendrimers
O
Me2N
O
O
O
O
O
h’’
Emission 530 nm
Naph
Dans
Eosin
Angew. Chem. Int. Ed. 2002, 41, 3595
• “We could use, not just circuits, but some systems
involving quantized energy levels, or the interaction
of quantized spins.”
Electron spin valves have
become the dominant
readout device in the disk
drives.
Spintronics
 
E1 
2mL2
2
• Particle in a box
2
Quantum dots
(Courtesy of Dylan M. Spencer)
Copyright (c) Stuart Lindsay 2008
• Fluctuations play a large role in small systems simply
because they are relatively larger in smaller systems.
Fluctuations scale as N/N with respect to the mean energy
But
N/N  1 in small systems
• Complexity is a rapidly increasing function of N:
AN

N
• Adequate complexity and fluctuation.
The critical size scale where fluctuations are big
enough and the system is complex enough is indeed
the nanoscale.
Copyright (c) Stuart Lindsay 2008