introduction to nanotechnology: what, why and how mark tuominen, umass, november 17, 2007 bnl...
TRANSCRIPT
Introduction to Nanotechnology:What, Why and How
Mark Tuominen, UMass, November 17, 2007
bnl
manchester
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
.
Red blood cell
6,000 nanometersDNA
3 nanometers
From DOE
A Few Nanostructures Made at UMass100 nm dots 70 nm nanowires 200 nm rings
12 nm pores 14 nm dots
13 nm rings 25 nm honeycomb14 nm nanowires
18 nm pores
150 nm holes
Nanotech: Why?
10 GB2001
20 GB2002
40 GB2004
80 GB2006
160 GB2007
Example: Advancement of the iPod
Hard driveMagnetic data storage
Uses nanotechnology!
Magnetic Data StorageA computer hard drive stores your data magnetically
Disk
N S
direction of disk motion
“ Write”Head
0 0 1 0 1 0 0 1 1 0 _ _
“ Bits” ofinformation
NS
“ Read”Head
Signalcurrent
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, orall 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
Nanostructuresmacroscale (3D) object
widthdepth
height
nanofilm, or nanolayer (2D)
nanowire,nanorod, ornanocylinder (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 aMotion JPEG OpenDML decompressor
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QuickTime™ and aMotion JPEG OpenDML decompressor
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... 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 = A t
V = 1 teaspoonful
A = 0.5 acre
~ 2 cm3
~ 2,000 m2
t = V/A
20,000,000 cm2
= 2 cm3
20,000,000 cm2
= 0.0000001 cm = 1 x 10-7 cm= 1 x 10-9 m= 1 nanometer (nm)
A monolayer NANOFILM (single layer of molecules)
~1 nm thickLangmuir film
An example of a FILM
This is an example of SELF-ASSEMBLY
Langmuir-Blodgett FilmMust control movablebarrier to keep constantpressure
multiple dips -multiple layers
Another film method,Thermal Evaporation
Vaporization or sublimation of a heated material onto a substrate in a vacuum chamber
vacuum~10-7 torr
sample
source
film
vacuumpump
QCM
vapor
resistive, e-beam, rf or laserheat source
Pressure must be held low to prevent contamination!
Au, Cr, Al, Ag, Cu, SiO, others
There are many otherthin film manufacturingtechniques
Nanofilm by Electroplating
VI
Cu2+ + 2e- –> Cu(0)
"reduction"
CuSO4 dissolved in water
Cu(0) –> Cu2+ + 2e-
"oxidation"
anodecathode
If using an inert Pt electrode:
2 H2O –> O2 + 4H+ + 4e-
WorkingElectrode(WE)
CounterElectrode(CE)
BREAK
Imaging NanostructuresAtomic Force Microscope (AFM)
.
"Optical Lever" for Profilometry
cantilever
laser
.
"Optical Lever" for Profilometry
cantilever
laser
Long light path and a short cantilever gives large amplification
Ato
mic
For
ce M
icro
scop
eA
tom
ic F
orce
Mic
rosc
ope
AFM Cantilever Chip AFM Instrument Head
Laser Beam Path Cantilever Deflection
Image of Nickel AtomsSTM
Lithography(controlling width and depth)
Lithography
MarkTuominen
MarkTuominen
MarkTuominen
(Using a stencil or mask)
Photolithography for Deposition
substrate
process recipe
spin on resist
resist
expose
mask (reticle)
develop
deposit
liftoffnarrow line
apply spin bake
spin coating
exposed unexposed
"scission"
Lithography
IBMCopperWiringOn aComputerChip
PatternedSeveral Times
Electron-Beam Lithography
Silicon crystal
Polymer film
Electron Beam
Nanoscopic Mask !
Self-Assembled Nanostructuresand
Lithography Based on Self-Assembly
Self Assembly
Diatoms
priweb.org
sinancanan.net
Gecko feet
Abalone
NANOFABRICATION BY SELF ASSEMBLY
Block “A” Block “B”
10% A 30% A 50% A 70% A 90% A
~10 nm
Ordered Phases
PMMA PS
Scale set by molecular size
Diblock Copolymers
CORE CONCEPT FOR NANOFABRICATION Deposition
Template
EtchingMask
NanoporousMembrane
Remove polymerblock within cylinders(expose and develop)
Versatile, self-assembling, nanoscale lithographic system
(physical orelectrochemical)
Application examples:Nanoelectronics
Computer
Microprocessor"Heart of the computer"
Does the "thinking"
Making Small SmallerAn Example: Electronics-Microprocessors
ibm.commacroscale
microscale
nanoscale
Electronics Keep On Getting BetterMoore'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
Granular Media
PerpendicularWrite Head
Soft Magnetic UnderLayer (SUL)
coil
Y. Sonobe, et al., JMMM (2006)
1 bit
• CHM Goal: Make "perfect" mediausing self-assembled nano-templates• Also, making new designs for storage
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nanoporous template
nanowires in a diblockcopolymer template
Electrodeposited Nanowires in aNanoporous Polymer Template (Mask)
1x1012 wires/in2
Benefit: Sun is an unlimited source of electronic energy.
Solar Cells
Konarka
Electric Solar CellsMade from single-crystal silicon wafers (conventionally)
cross-sectional view
n-type silicon
p-type silicon
+
-
Sunlight
Voltage “load”
+
-
Current
The load can be a lamp, an electric motor, a CD player, a toaster, etc
wires
Nanostructured Solar Cells
+
-
Sunlight
Voltage “load”
CurrentMore interface area - More power!
Nanotechnology R&D is interdisciplinary and impacts many applications
• 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!