E SC 412

Nanotechnology: Materials, Infrastructure, and Safety

Wook Jun Nam

1. What is “nanotechnology”?

2. How small is a nanometer ?

3. Nanotechnology in history:

a) Optical properties

b) Mechanical properties

4. Why nanotechnology is so big now ?

Outline

• The word ”nano” originally comes

from Greek. In Roman times (2000

years ago) it meant “dwarf”. In

modern Italian, it still means “dwarf”.

• The prefix nano means

1 billion

– Denoted as 1 X 10-9 or nm

• Nano-products have features 100nm

or smaller

How many atoms lined up do you think it

takes to make one nm?

Red blood cells(~7-8 mm)

Fly (coal) ash~ 10-20 mmHuman hair

~ 60-120 mm wide

Ant~ 5 mm

Dust mite

200 mm

Scale of Things

Things Natural

Atoms of siliconspacing

0.078 nm

DNA~2-1/2 nm diameter

Mic

row

orl

d

0.1 nm

1 nanometer (nm)

0.01 mm

10 nm

0.1 mm

100 nm

1 micrometer (mm)

0.01 mm

10 mm

0.1 mm

= 100 mm

1 cm

10 mm10-2

10-3

10-4

10-5

10-6

10-7

10-8

10-9

10-10

Vis

ible

Nan

ow

orl

d

1,000 nanometers =

Infr

ared

Ult

ravi

ole

tM

icro

wav

eS

oft

x-r

ay

1,000,000 nanometers

= 1 millimeter (mm)

Ma

cro

wo

rld

ATP Synthase

Protein (enzyme)

~10 nm

What is Nanotechnology ?

Meter 100 Centimeter 10-2 Millimeter 10-3

Micrometer 10-6 Nanometer 10-9 Angstrom 10-10

How small is a nanometer ??

Another Way of Looking at How Small a Nanometer is-

Courtesy of NanoHorizons, Inc.

Museum of Science, Boston

Movie

Still another way of looking at how small a nanometer is-

(1990’s)Second Generation (2G) cell phones started using digital signals

(1986)First IBM-compatibleLaptop Toshiba T1100CPU 80C86 @ 7.16 MHz640K RAM, 2 Floppies9 lbs

(2007)16 GB (23,000 Floppies)Phone, Camera, GPSAccelerometerProximity SensorLight Sensor5-10 hr Battery4.7 oz

(1969) The first iPhone had

more memory and

computational power

than Apollo rockets or

lunar module that

took us to the moon

Smaller is better: an example

• Over time transistors

became easier to make

• This all lead to reduced cost

• Transistor production

became more common,

making the equipment and

techniques for

nanotechnology readily

obtainable

• The price of a transistor is

estimated to be the same or

less than a single printed

character (letter) on a

newspaper!!!

286

486

Pentium 4

Core 2 Duo

4004

8008 8080

8086

906545

32

130180

Microchips, Moore’s Law, and Cost

• Using nano-scale materials and understanding them are two

different things!

Zeiss Ultra 60

Modern tools:

•Help us to see and

manipulate matter at the nano-

scale

•Allow us to understand how

(and why) the small structures

work

Field Emission Scanning Electron Microscope (FESEM)

Nano: Enabling Technologies

Atomic Force Microscope(AFM)

Veeco Model CP-II

Depiction of AFM probe tip

I B M spelled out with Xenon Atoms on a Nickel Surface by an STM-based

tool

Nano: Enabling Technologies

Macro-scale ● The sizes of things we’re accustomed to

using and seeing; i.e., anything bigger than

about a millimeter

Micro-scale ● Smaller than the macro-scale

● Sizes from about one millionth of a

meter to one ten thousandth of a meter;

i.e., sizes from about a micrometer to

about 1/10 of a millimeter

Nano-scale: ● Smaller than the micro-scale. Really small !

● Sizes from one billionth of a meter

to one ten millionth of a meter; i.e., sizes from

about a nanometer to about 1/10 of a

micrometer.

Definitions of Different Size Ranges

Meter

Size Range

These are

sizes we can

see with just

our eyes

Millimeter

Size Range

These are

sizes we can

see with an

optical

microscope

Micrometer

Size Range

Bigger objects

in this range

can be seen

with an optical

microscope.

Smaller objects

may need an

electron

microscope

Nanometer

Size Range

Bigger objects

can be seen

with electron

microscopes.

Smaller objects

require field

emission

electron or

atomic force

microscopes

MACRO-SCALE NANO-SCALEMICRO-SCALE

How do we see things in these different size ranges ?

Let’s look at these size ranges

pictorially

Let’s also get some idea of what

nature makes and what man makes

in these size ranges

The next viewgraph may

be useful for remembering how

small the nano-scale size range is.

As this viewgraph shows, the nano-

scale range covers sizes from that of

viruses down to structures with a few

atoms (quantum dots).

1 m

m

10

0 µ

m

10

µm

1 µ

m

10

0 n

m

10

nm

1 n

m

10

0 p

m

Transistor of 2007

Human hair

tissue

Bacterium cell

Human cell

Virus

Transistors of 20-30 Years ago

Protein

Individual atom

Drug molecule Quantum dot

DNA

Nano-scaleMicro-scaleMacro-scale

-

--

-

-

-

Sizes of some small natural and man-made structures

Also note from our pictorial representation

of scales that the next size range that is

smaller than the nano-scale is the pico-

scale

What’s after Nanotechnology – Is there a

Picotechnology?

No, nothing to build at the pico-scale

• Note that neither nature nor man builds anything at this

pico-scale size range.

• It is the size range of the basic “legos” used to build

everything – individual atoms

“Nanotechnology is the builder’s final frontier.”

Richard Smalley1996 Nobel Laurate in Chemistry, Rice University

Nanotechnology has actually

been practiced by humans

for over 2000 years

Nanotechnology in History

Nanotechnology in History:

Optical Properties

(a) Reflected light and (b) Transmitted light

Nanotechnology in History: The Lycurgus Cup

Ian Freestone et. al., Gold Bulleting, 40(4), 270, (2007)

Nanotechnology in History: The Lycurgus Cup

• In reflected light, cup

appears green; in

transmitted light, it appears

red

• 40 ppm Au nanoparticles&

300 ppm Ag nanoparticles

embedded in soda-lime-

silica glass

• Au component being mainly

responsible for the reddish

transmission and the Ag for

the greenish reflection.

Ian Freestone et. al., Gold Bulleting, 40(4), 270, (2007)

Nanotechnology in History: The Lycurgus Cup

• The colors of the cup are

produced by precise (1)

colloidal concentration (2)

particle diameter, and (3)

proportions and oxidation

states of certain elements.

• The diameters of the alloy

nanoparticles are typically

50~ 100nm.

TEM image of a Ag-Au alloy particle within the glass

of the Lycurgus Cup

Ian Freestone et. al., Gold Bulleting, 40(4), 270, (2007)

Nanotechnology in History: The Lycurgus Cup

• (a) reflected light and (b)

transmitted light

• Ag rich Roman glass: 13ppm

Au & 2270ppm Ag

We now know that the beautiful

stained-glass windows made 1600

years ago by the ancient Irish also

used nanotechnology

Armagh, Ireland, AD 444

We now know that beautiful plates

made by the Renaissance Italians

500 years ago also used

nanotechnology

Reprinted with permission from Journal of Applied

Physics, Vol. 93, Issue 12, P.10058, 2003, American

Institute of Physics.

16th century Renaissance pottery

The Renaissance

Italians used what

we now know to be

copper and silver

nanoparticles to

achieve this vibrantly

colored pottery.

Again, we don’t know

the details of how

they did it.

Nanotechnology in History:

Mechanical Properties

Carbon nanotubes and carbon

nanowires in Damascus steel

sword.

Nanotechnology in History: Damascus Blade

• Arab craftsmen made steel swords of legendary strength.

• Such blades were reputed to be not only tough and resistant to shattering, but capable of being honed to a sharpand resilient edge

Reibold, M., et al. "Carbon Nanotubes in an Ancient Damascus Sabre." Nature 444 (2006).

Nanotechnology in History: Damascus Blade

• Reibold’s team dissolved part of the weapon in hydrochloric acid and studied it under an electron microscope.

• The steel contained carbon nanotubes, each one just slightly larger than half a nanometer.

• Ten million could fit side by side on the head of a thumbtack.

German Wikipedia, original upload 29. Dez 2004 by APPER

Nanotechnology in History: Damascus Blade

• Carbon nanotubes are cylinders made of hexagonally-arranged carbon atoms. They are among the strongest materials known and have great elasticity and tensile strength.

• In Reibold’s analysis, the nanotubes were protecting nanowires of cementite (Fe3C), a hard and brittle compound formed by the iron and carbon of the steel.

Reibold, M., et al. "Carbon Nanotubes in an Ancient Damascus Sabre." Nature 444 (2006).

Nanotechnology in History: Damascus Blade

• That is the answer to the steel’s special properties – it is a composite material at a nanometer level.

• The malleability of the carbon nanotubes makes up for the brittle nature of the cementite formed by the high-carbon wootz cakes.

If nanotechnology has been

practiced by humans for almost

2000 years, why is it taking off

now?

Why is it so “big” now?

Because we have learned what’s going on-

• We can now controllably and repeatedly

make things in the nano-size range

• And finally we can now see what we have

made

We now know that a cup made by the Romans 1700 years ago used

nanotechnology!

(We just found out because we

just learned how to see the nanoparticles they used)

Ian Freestone et. al., Gold Bulleting, 40(4), 270, (2007)

Analysis Progress: The Lycurgus Cup

• 1845

:first mentioned in print

• 1950~1959

: it was made of glass (XRD)

: soda-lime-silica type glass

(0.5% of Mg, 1% of Ag and

Au)

• 1962

:concentration of Au (40ppm)

and Ag (300ppm)

• 1980

:50~100nm of particle size

:contribution of NaCl particles

• For example, today’s transistors are nano-scale structures

• Today more nano-scale transistors are made in a year than there are grains of rice grown in a year—now that’s control and repeatability!

• We have really learned how to build at the nano-scale!

We can controllably and repeatedly make things

in the nano-scale range

• The following picture is a cross-section of an actual man-made transistor (circa 2002). This is a FET transistor in which, in the on-state, electrons travel from the source to the drain by going down the 50 nm long “channel” of this particular transistor under its gate

• This sample has been made by cutting a chip containing millions of transistors and looking at the cross-section to focus on one transistor. The imaging is done with a scanning electron microscope (SEM)

Adapted from Linda Geppert, The Amazing Vanishing Transistor Act, IEEE Spectrum, October

2002, Vol. 39, Number 10, pg. 28-33

We can now see what we have made!

We can even routinely see atoms now!

• The next view graph shows 48 atoms that have been

dragged across a surface (itself, of course, made of atoms)

and arranged into a circle (a corral). This arrangement has

been given the name “Quantum Corral”

• If you look closely, you can see the individual atoms of the

corral, all of which are sitting on the underlying surface. If

you look very closely, you also can see the atoms that

make up that underlying surface. The dragging of the

atoms and the imaging is done using a scanning tunneling

microscope.

M.F. Crommie, C.P. Lutz, D.M. Eigler. Confinement of electrons to quantum corrals on a metal surface.Science 262, 218-220 (1993).

Quantum Corral

Atomic Manipulation

http://www.youtube.com/watch?v=BUq2bQkL

1zo

Atomic Manipulation Application

http://www.youtube.com/watch?v=f2OKVQm

ODC8

• The nano-scale refers to sizes from 1nm to about 100nm (or from the size of a few atoms in a row to the size of a virus)

• Nanotechnology is the making and using of “things” which are in this size range

• Nanotechnology is “the builders last frontier”

• Nanotechnology has actually been around awhile – almost 2000 years !

• Nanotechnology is emerging now because

1. We’ve learned how to see what we’ve made (to check it, understand and manipulate it)

2. We’ve learned how to make things that small with control and repeatability

Key Ideas

• Because of the advances that have very recently been

achieved in what we can make and what we can see,

nanotechnology is now manufacturable.

• Nanotechnology can now produce things in huge numbers

and economically

Key Ideas (continued)