1. Introduction to Nanotechnology:
What, Why and How
bnl
manchester
Mark Tuominen, UMass, November 17, 2007

2. Nanotech: What?

3. 1 nanometer = 1 billionth of a meter
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

4. How small are nanostructures?
Single Hair
Width = 0.1 mm
= 100 micrometers
= 100,000 nanometers !
1 nanometer = one billionth (10-9) meter

5. Smaller still
DNA
3 nanometers
6,000 nanometers
Hair
Red blood cell .

6. From DOE

7. A Few Nanostructures Made at UMass
100 nm dots
70 nm nanowires
200 nm rings
150 nm holes
18 nm pores
12 nm pores
14 nm dots
13 nm rings
25 nm honeycomb
14 nm nanowires

8. Nanotech: Why?

9. 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!

10. Magnetic Data Storage
A computer hard drive stores your data magnetically
“Read”
Head
Signal
“Write”
Head
current S N
Disk N S 1 _
“Bits” of
information
direction of disk motion

11. 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!

12. 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.)

13. Nanotech: How? How to make nanostructures?
How to characterize and test them?

14. Making Nanostructures: Nanofabrication
Top down versus bottom up methods
Lithography
Deposition
Etching
Machining
Chemical
Self-Assembly

15. Nanostructures nanofilm, macroscale (3D) object or nanolayer (2D)
height
depth
width
nanoparticle,
nanodot,
quantum dot (0D)
nanowire,
nanorod, or
nanocylinder (1D)

16. Nanofilms (making thin objects)

17. An Early Nanotechnologist?

18. Excerpt from Letter of Benjamin Franklin to William Brownrigg (Nov
...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....

21. CHALLENGE: How thick was the film of oil?
... 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
t = V/A =
2 cm3
20,000,000 cm2
V = 1 teaspoonful
A = 0.5 acre
~ 2 cm3
~ 2,000 m2
= cm
= 1 x 10-7 cm
= 1 x 10-9 m
= 1 nanometer (nm)
20,000,000 cm2

22. An example of a FILM A monolayer NANOFILM (single layer of molecules)
~1 nm thick
Langmuir film
This is an example of SELF-ASSEMBLY

23. Langmuir-Blodgett Film
Must control movable
barrier to keep constant
pressure
multiple dips -
multiple layers

24. Another film method, Thermal Evaporation
sample
QCM
Vaporization or sublimation of a heated material onto a substrate in a vacuum chamber
film
vapor
Au, Cr, Al, Ag, Cu, SiO, others
Pressure must be held low
to prevent contamination!
vacuum
~10-7 torr
source
There are many other
thin film manufacturing
techniques
resistive, e-beam, rf or laser
heat source
vacuum
pump

25. Nanofilm by ElectroplatingV
cathode
anode
CuSO4 dissolved in water
Working
Electrode
(WE)
Counter
(CE)
Cu(0) –> Cu2+ + 2e-
"oxidation"
If using an inert Pt electrode:
2 H2O –>
O2 + 4H+ + 4e-
"reduction"
Cu2+ + 2e- –> Cu(0)

26. BREAK

27. Imaging Nanostructures Atomic Force Microscope (AFM)

28. "Optical Lever" for Profilometry
laser .
cantilever

29. "Optical Lever" for Profilometry
Long light path and a short cantilever gives large amplification
laser .
cantilever

30. Atomic Force Microscope
AFM Cantilever Chip
AFM Instrument Head
Atomic Force Microscope
Laser Beam Path
Cantilever Deflection

31. STM
Image of Nickel Atoms

32. Lithography (controlling width and depth)

33. Mark Tuominen Mark Tuominen
Lithography
Mark
Tuominen
Mark
Tuominen
(Using a stencil or mask)

34. Photolithography for Deposition
process recipe
apply
spin
bake
spin coating
substrate
spin on resist
resist
expose
mask (reticle)
exposed
unexposed
"scission"
develop
narrow line
deposit
liftoff

35. Lithography Patterned Several IBM Times Copper Wiring On a Computer
Chip

36. Electron-Beam Lithography
Polymer film
Silicon crystal
Nanoscopic Mask !

37. Self-Assembled Nanostructures and Lithography Based on Self-Assembly

38. Self
Assembly

39. Diatoms
sinancanan.net
priweb.org

40. Gecko feet

41. Abalone

42. NANOFABRICATION BY SELF ASSEMBLY
Diblock Copolymers
Block “B”
Block “A” PS
PMMA
~10 nm
Scale set by molecular size
Ordered Phases
10% A
30% A
50% A
70% A
90% A

43. Versatile, self-assembling, nanoscale lithographic system
CORE CONCEPT
FOR NANOFABRICATION
Deposition
Template
Etching
Mask
Nanoporous
Membrane
(physical or
electrochemical)
Remove polymer
block within cylinders
(expose and develop)
Versatile, self-assembling, nanoscale lithographic system

44. Application examples: Nanoelectronics

45. Computer
Microprocessor
"Heart of the computer"
Does the "thinking"

46. Making Small Smaller An Example: Electronics-Microprocessors
microscale
nanoscale
macroscale
ibm.com

47. Electronics Keep On Getting Better
Moore's "Law": Number of Transistors per Microprocessor Chip
intel.com

48. Hard Disk Drives - a home for bits
Hitachi

49. Magnetic Data Storage ? N S ‘0’ N S S N S N ‘1’ Current
Magnet with unknown magnetic state N S S N S
Current N
‘1’

50. Binary Representation of Data
only 2 choices
one bit
“1” or “0”
two bits
00, 01, 10, 11
4 choices
three bits
000, 001, 010, 011,
100, 101, 110, 111
8 choices
n bits has 2n choices
For example, 5 bits has 25 = 32 choices...
more than enough to represent all the letters of the alphabet

51. Binary representation of lower case letters
5-bit "Super Scientist" code:
ex: k = 01011 1 S N OR
(Coding Activity: Use attractive and repulsive forces to "read" the magnetic data!)

52. Improving Magnetic Data Storage Technology
The UMass Amherst Center for Hierarchical Manufacturing is working to improve this technology
Granular Media
Perpendicular
Write Head
Soft Magnetic UnderLayer (SUL)
coil
1 bit
Y. Sonobe, et al., JMMM (2006)
• CHM Goal: Make "perfect" media
using self-assembled nano-templates
• Also, making new designs for storage

53. Electrodeposited Nanowires in a Nanoporous Polymer Template (Mask)
nanowires in a diblock
copolymer template
nanoporous template
Pulse reverse electrodeposition results in improved microcrystalline structure and improved magnetic properties (larger perpendicula magnetocrystalline anisotropy)
1x1012 wires/in2

54. Solar Cells Benefit: Sun is an unlimited source of electronic energy.
Konarka

55. Electric Solar Cells Sunlight - + + -
Made from single-crystal silicon wafers (conventionally)
Sunlight
wires -
cross-sectional view
“load”
n-type silicon
Voltage
p-type silicon + + -
Current
The load can be a lamp, an electric motor, a CD player, a toaster, etc

56. Nanostructured Solar Cells
Sunlight -
“load”
Voltage +
Current
More interface area - More power!

57. 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

58. Thanks for visiting UMass and learning about nanotechnology!