Transcript Nanofabrication - MIT - Massachusetts Institute of Technology

Nanofabrication
H. Hau Wang
Argonne National Laboratory
Materials Science Division
[email protected]
Symposium on Digital Fabrication
Aug 12, 2005
Argonne National Laboratory is managed by
The University of Chicago for the U.S. Department of Energy
Why going Nano?
1 nm = 10-9 m
 Chemistry – higher reactivity
High surface area – Good for chemical and biochemical sensors
Higher sensitivity and faster response time
Good for heterogeneous catalysis
The larger the surface area, the higher the reactivity.
High level of reaction control
 Material – better mechanical strength
UNCD Ultra-nano-crystalline diamond (ANL/CNM)
Ultra-thin and tough coating - prolong equipment life time
Carbon-nanotubes – Ultra-high mechanical strength
 Physics – quantum confined phenomena and designed physical properties
Quantum dots,
Near field optics, plasmonics
High density magnetic storage – nanoclusters
Ideal spring nanomagnet - High magnetization and coercivity
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Nanofabrication – current status
 Top-down Fabrication techniques
e-beam lithography
FIB – focused ion beam
DPN – dip pen nanolithography
Requires major facilities, control below 100 nm is a challenge, can not
obtain high aspect ratio.
 Bottom-up Synthesis
– The nano-scaled objects are limited to simple geometrical shape:
sphere, cube, triangle, thin film, wire, tube, etc.
– No standard 3D morphological control
– Handling and Alignment are difficult
 Lithographically assisted self-assembly – Combining top-down and bottom-up
1 x 1 mm2 AFM image of
self-assembled PEGPMMA thin film showing
partially ordered
structure
5 x 5 mm2 AFM image of
as-prepared AAO
membrane showing
domain boundary
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Nanotubes
 AAO/Al2O3/V2O5 nanostructure has been prepared for
heterogeneous catalysis studies.
 Pd nanotubes showed very good hydrogen sensing capability.
Before ALD
After ALD
Cross-Section of
Coated AAO
200 nm Bi NT
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Nanoparticles
 Au, Co, Co/Pt
Nanoparticles
– Magnetic
storage
(X. M. Lin et al.)
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Dynamics of Monolayer Nanocrystal Self-assembling Process in Liquid Film
To understand the dynamics of
highly ordered nanocrystal
monolayer through evaporation of
a nanocrystal colloidal droplet.
(J. Phys. Chem. B 2001, 105,
3353)
Grazing Incidence Small Angle
X-ray Scattering (GISAXS)
 Kinetic effects can play an important role in nanocrystal self-assembly.
 Fast initial evaporation rate can induce nanocrystals accumulate at the
liquid-air interface and undergo a 3D to 2D structural transition to form
highly ordered nanocrystal monolayer.
Xiao-Min Lin
MSD/CHM
Suresh Narayanan, Jin Wang
Advanced Photon Source
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50 nm Au
Nanowires
 Various metallic (Au, Ag, Cu, etc.), superconductive
(Pb), ferromagnetic (Co, Ni, etc.) nanowires have
been made with anodized aluminum oxide (AAO)
templates.
Co 20 nm/Cu 20 nm
 Multi-segmented (Co/Cu), (Au/Ni – Mirkin, Science
2005) nanowires have been prepared with pulsed
electro-deposition.
 Multi-segmented SiNi/Si/SiNi nanowires have been
fabricated into integrated nanowire circuits. (Lieber,
Nature 2005)
http://WWW.anl.gov/
Materials Science Division, MSD
Center for Nanoscale Materials, CNM
M
AP
FM1 (Co)
NM (Cu)
FM2 (Co)
R
Parallel
AP
H
Parallel
DR/R
H
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