Download Nanotechnology overview by Mark Tuominen

Introduction to Nanotechnology:
What, Why and How
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Mark Tuominen, UMass, November 17, 2007
Nanotech: What?
Nanotechnology
Nanotechnology is the understanding
and control of matter at dimensions of
roughly 1 to 100 nanometers, where
unique phenomena enable novel
applications.
1 nanometer = 1 billionth of a meter
= 1 x 10-9 m
nano.gov
How small are
nanostructures?
Single Hair
Width = 0.1 mm
= 100 micrometers
= 100,000 nanometers !
1 nanometer = one billionth (10-9) meter
Smaller still
Hair
6,000 nanometers
DNA
.
Red blood cell
3 nanometers
From DOE
A Few Nanostructures Made at UMass
100 nm dots
18 nm pores
70 nm nanowires
12 nm pores
14 nm nanowires
13 nm rings
200 nm rings
14 nm dots
25 nm honeycomb
150 nm holes
Nanotech: Why?
Example: Advancement of the iPod
10 GB
2001
20 GB
2002
40 GB
2004
80 GB
2006
160 GB
2007
Hard drive
Magnetic data storage
Uses nanotechnology!
Magnetic Data Storage
A computer hard drive stores your data magnetically
“Read”
Head
“Write”
Head
Signal
S
N
N
S
0
1
current
Disk
0
0
1
0
0
1
direction of disk motion
1
0
_
_
“Bits” of
information
Scaling Down to the Nanoscale
Increases the amount of data stored
on a fixed amount of “real estate” !
Now ~ 100 billion bits/in2, future target more than 1 trillion bits/in2
25 DVDs on a disk the size of a quarter, or
all Library of Congress books on a 1 sq ft tile!
Why do we want to make
things at the nanoscale?
• To make better and new products: smaller,
cheaper, faster and more effective.
(Electronics, catalysts, water purification,
solar cells, coatings, medical diagnostics &
therapy, etc)
• To introduce completely new physical
phenomena to science, technology.
(Quantum behavior and other effects.)
Nanotech: How?
• How to make nanostructures?
• How to characterize and test them?
Making Nanostructures:
Nanofabrication
• Top down versus bottom up methods
•Lithography
•Deposition
•Etching
•Machining
•Chemical
•Self-Assembly
Nanostructures
macroscale (3D) object
nanofilm,
or nanolayer (2D)
height
depth
width
nanowire,
nanorod, or
nanocylinder (1D)
nanoparticle,
nanodot,
quantum dot (0D)
Nanofilms
(making thin objects)
An Early Nanotechnologist?
Excerpt from Letter of Benjamin Franklin to William Brownrigg (Nov. 7, 1773)
...At length being at Clapham, where there is, on the Common, a large
Pond ... I fetched out a Cruet of Oil, and dropt a little of it on the Water. I
saw it spread itself with surprising Swiftness upon the Surface ... the Oil
tho' not more than a Tea Spoonful ... which spread amazingly, and
extended itself gradually till it reached the Lee Side, making all that
Quarter of the Pond, perhaps half an Acre, as smooth as a Looking
Glass....
QuickTime™ and a
Motion JPEG OpenDML decompressor
are needed to see this picture.
QuickTime™ and a
Motion JPEG OpenDML decompressor
are needed to see this picture.
... the Oil tho' not more than a Tea Spoonful ...
... perhaps half an Acre
CHALLENGE: How thick was the film of oil?
Volume = (Area)(Thickness)
V=At
t = V/A
V = 1 teaspoonful
A = 0.5 acre
2 cm3
20,000,000 cm2
~ 2 cm3
=
~ 2,000 m2
= 0.0000001 cm
= 1 x 10-7 cm
= 1 x 10-9 m
= 1 nanometer (nm)
20,000,000 cm2
An example of a FILM
A monolayer NANOFILM (single layer of molecules)
~1 nm thick
Langmuir film
This is an example of SELF-ASSEMBLY
Langmuir-Blodgett Film
Must control movable
barrier to keep constant
pressure
multiple dips multiple layers
Another film method,
Thermal Evaporation
Vaporization or sublimation of a
heated material onto a substrate
in a vacuum chamber
sample QCM
film
vapor
Au, Cr, Al, Ag, Cu, SiO, others
Pressure must be held low
to prevent contamination!
There are many other
thin film manufacturing
techniques
vacuum
~10-7 torr
source
resistive, e-beam, rf or laser
heat source
vacuum
pump
Nanofilm by Electroplating
I
V
cathode
Working
Electrode
(WE)
CuSO4 dissolved in water
anode
Counter
Electrode
(CE)
If using an inert Pt
electrode:
2 H2O –>
O2 + 4H+ + 4e-
"reduction"
Cu2+ + 2e- –> Cu(0)
"oxidation"
Cu(0) –> Cu2+ + 2e-
BREAK
Imaging Nanostructures
Atomic Force Microscope (AFM)
"Optical Lever" for Profilometry
laser
cantilever
.
"Optical Lever" for Profilometry
laser
Long light path and a
short cantilever gives
large amplification
cantilever
.
AFM Instrument Head
Atomic Force Microscope
AFM Cantilever Chip
Laser Beam Path
Cantilever Deflection
STM
Image of Nickel Atoms
Lithography
(controlling width and depth)
Lithography
Mark
Tuominen
(Using a stencil or mask)
Photolithography for Deposition
process recipe
spin coating
substrate
apply
spin
bake
spin on resist
resist
expose
mask (reticle)
exposed
unexposed
"scission"
develop
deposit
liftoff
narrow line
Lithography
IBM
Copper
Wiring
On a
Computer
Chip
Patterned
Several
Times
Electron-Beam Lithography
Electron Beam
Polymer film
Silicon crystal
Nanoscopic Mask !
Self-Assembled Nanostructures
and
Lithography Based on Self-Assembly
Self
Assembly
Diatoms
sinancanan.net
priweb.org
Gecko feet
Abalone
NANOFABRICATION BY SELF ASSEMBLY
Diblock Copolymers
Block “B”
PS
Block “A”
PMMA
~10 nm
Scale set by molecular size
Ordered Phases
10% A
30% A
50% A
70% A
90% A
CORE CONCEPT
FOR NANOFABRICATION
Deposition
Template
(physical or
electrochemical)
Etching
Mask
Remove polymer
block within cylinders
(expose and develop)
Nanoporous
Membrane
Versatile, self-assembling, nanoscale lithographic system
Application examples:
Nanoelectronics
Computer
Microprocessor
"Heart of the computer"
Does the "thinking"
Making Small Smaller
An Example: Electronics-Microprocessors
microscale
nanoscale
macroscale
ibm.com
Electronics Keep On Getting Better
Moore's "Law": Number of Transistors per Microprocessor Chip
intel.com
Hard Disk Drives - a home for bits
Hitachi
Improving Magnetic Data Storage Technology
• The UMass Amherst Center for Hierarchical
Manufacturing is working to improve this
technology
coil
1 bit
Perpendicular
Write Head
Granular Media
Soft Magnetic UnderLayer (SUL)
Y. Sonobe, et al., JMMM (2006)
• CHM Goal: Make "perfect" media
using self-assembled nano-templates
• Also, making new designs for storage
QuickTime™ and a
TIFF (LZW) decompressor
are needed to see this picture.
Electrodeposited Nanowires in a
Nanoporous Polymer Template (Mask)
nanowires in a diblock
copolymer template
nanoporous template
1x1012 wires/in2
Solar Cells
Benefit: Sun is an unlimited source of electronic energy.
Konarka
Electric Solar Cells
Made from single-crystal silicon wafers (conventionally)
Sunlight
wires
-
cross-sectional view
n-type silicon
Voltage
p-type silicon
+
-
Current
“load”
+
The load can be a lamp, an electric
motor, a CD player, a toaster, etc
Nanostructured Solar Cells
Sunlight
Voltage
More interface area - More power!
Current
“load”
+
Nanotechnology R&D is
interdisciplinary and impacts many applications
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Physics
Chemistry
Biology
Materials Science
Polymer Science
Electrical Engineering
Chemical Engineering
Mechanical Engineering
Medicine
And others
• Electronics
• Materials
• Health/Biotech
• Chemical
• Environmental
• Energy
• Aerospace
• Automotive
• Security
• Forest products
• And others
Thanks for visiting UMass and
learning about nanotechnology!