introduction to nanotechnology
Post on 04-Jan-2016
369 Views
Preview:
DESCRIPTION
TRANSCRIPT
Introduction to NanotechnologyJuly 23, 2007
bnl
manchester
Some things we will discuss:
• How big are nanostructuresScaling down to the nanoscale
• How are nanostructures made?Fabrication, synthesis, manufacturing
• How do we see them?Imaging and property characterization (measurement)
• Why do we care?Applications to science, technology and society
Introduction to NanotechnologyJuly 23, 2007
Why do we want to make things at the nanoscale?
• To make better 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 and technology. (Quantum behavior and other effects.)
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 x 10-9 m= 1 billionth of a meter
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
Down to the Nanoscale
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
"Nano"
• Nanoscale - at the 1-100 nm scale, roughly• Nanostructure - an object that has nanoscale
features• Nanoscience - the behavior and properties of
nanostructures• Nanotechnology - the techniques for making and
characterizing nanostructures and putting them to use
• Nanomanufacturing - methods for producing nanostructures in reliable and commercially viable ways
Nanotechnology R&D is interdisciplinary and impacts many industries
• 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
An application example:Nanoelectronics
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
Since the 1980's electronics has been a leading commercial driver for nanotechnology R&D, but other areas (materials, biotech, energy, etc) are of significant and growing importance.
Some have been around for a very long time:• Stained glass windows (Venice, Italy) - gold nanoparticles• Photographic film - silver nanoparticles• Tires - carbon black nanoparticles• Catalytic converters - nanoscale coatings of platinum and palladium
QuickTime™ and aTIFF (LZW) decompressor
are needed to see this picture.
"Biggest science initiative since the Apollo program"
nano.gov
National Nanotechnology InitiativeResearch Areas (2007 Federal Budget)
1.Fundamental Nanoscale Phenomena and Processes2.Nanomaterials3.Nanoscale Devices and Systems4.Instrumentation Research, Metrology and Standards for Nanotechnology5.Nanomanufacturing6.Major Research Facilities and Instrumentation Acquisition7.Societal Dimensions
nanomanufacturing.org
A National Science Foundation Nano Center
Nanostructures
Nanostructuresmacroscale (3D) object
widthdepth
height
nanofilm, or nanolayer (2D)
nanowire,nanorod, ornanocylinder (1D)
nanoparticle,nanodot,quantum dot (0D)
Making Nanostructures: Nanofabrication
• Top down versus bottom up methods
•Lithography•Deposition•Etching•Machining
•Chemical•Self-Assembly
Nanofilms(making an object thin)
A monolayer NANOFILM (single layer of molecules)
~1 nm thickLangmuir film
An example of a FILM
This is an example of SELF-ASSEMBLY
... 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)
QuickTime™ and aTIFF (LZW) decompressor
are needed to see this picture.
LangmuirFilm pressure
e.g., oleic acid
monolayer filmwater
hydrophilic end
hydrophobic end
of an amphiphilicmolecule
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
Lithography(controlling width and depth)
Lithography
MarkTuominenMark
TuominenMark
Tuominen
(Using a stencil or mask)
Making a nanoscopic mask
Silicon crystal
Polymer film
Electron Beam
Nanoscopic Mask !
Example: Electron-Beam Lithography
Lithography
IBMCopperWiringOn aComputerChip
PatternedSeveral Times
Self-Assembled Nanostructures
Self
Assembly
Tobacco Mosaic Virus
wisc.edu
nih.gov
Gecko feet
Diatoms
priweb.org
sinancanan.net
Abalone
The Cell and Its Hierarchy
ebi.ac.uk
Whitesides et al. Science 295, 2418 (2002);
Self assembly at all scales?
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
One Example: 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)
NANOFABRICATIONUSING DIBLOCK COPOLYMER TEMPLATES
template dots
rings holescylinders
Measuring Nanostructures
How do we see nanostructures?
• A light microscope? Helpful, but cannot resolve below 1000 nm
• An electron microscope? Has a long history of usefulness at the nanoscale
• A scanning probe microscope? A newer tool that has advanced imaging
Television Set
eye
electron beam
TV screen
Light !electronsource
prelim.
Scanning Electron Microscope
SAMPLE
ElectronBeam
DETECTOR
(Atomic Force Microscope) "Optical Lever"
To determine amplification factor, use the concept of similar triangles
laser pointer
Scanning probe microscope
Surface
Vibrating Cantilever
PS/PEO
AFM image
µm(large )
Laser Beam
AFM, STM, MFM, others
Qui
cktim
eQ
uick
time
AFM Cantilever Chip AFM Instrument Head
Laser Beam Path Cantilever Deflection
Scanning probe microscope
Surface
Vibrating Cantilever
PS/PEO
AFM image
µm(large )
Laser Beam
AFM, STM, MFM, others
Image of Nickel AtomsSTM
Pushing Atoms Around
STM
"Optical Lever"
y1
x1
y2
x2
€
y2x2=y1x1
€
y2 =x2x1y1
For example, if the laser pointer is 2" long, and the wall is 17' (204") away,
€
y2 =204
2y1 ≈100y1 Motion amplified
by 100 times!
.
"Optical Lever" for Profilometry
cantilever
laser
.
"Optical Lever" for Profilometry
cantilever
laser
Long light path and a short cantilever gives large amplification
top related