Introduction Outline

1. Where does the word “” come from and what does it mean? 2. Size ranges a) The macroscale b) The microscale c) The nanoscale 3. Nanotechnology – “the builder’s final frontier” 4. How old is nanotechnology? 5. Why is nanotechnology taking off now? a) We can now make small things controllably and repeatedly b) We can now see what we made 6. Key ideas First of all: What does the prefix “nano” mean?

The word ”nano” originally comes from Greek. In Roman times (2000 years ago) it meant “dwarf”. In modern Italian, it still means “dwarf”.

Today, in Scientific usage, it means really, really, really small or, more precisely, it is a prefix meaning 1 / 1,000,000,000 (one billionth) of something So What Does the Word “Nanotechnology” Mean?

It means based on man-made things that are really, really, really small or more precisely it means technology based on man-made things whose sizes are in the range of one billionth of a meter How small is

1 1,000,000,000

of a meter? How Small is a Nanometer?

1 meter = 3.28 feet

1 / 100 meter = 1 centimeter (cm)

1 / 1000 meter = 1 millimeter (mm)

1 / 1,000,000 meter = 1 micrometer* (µm) *also called a micron 1 / 1,000,000,000 meter = 1 nanometer (nm)

1 / 1,000,000,000,000 meter = 1 picometer (pm) Another way of looking at how small a Nanometer is- Definitions of Different Size Ranges 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. How Do We See Things in These Different Size Ranges?

MACRO-SCALE MICRO-SCALE NANO-SCALE Meter Millimeter Micrometer Nanometer Size Range Size Range Size Range Size Range These are These are Bigger objects Bigger objects sizes we can sizes we can in this range can be seen see with just see with an can be seen with electron our eyes optical with an optical . microscope. Smaller objects Smaller objects require field may need an emission electron electron or microscope atomic force microscopes 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 down to structures with a few (quantum dots). Sizes of Some Small Naturally Occurring and Man-Made Structures

Transistor of 2007 of 20-30 Years ago 1 nm 1 1 µm 1 1 mm 1 10 nm 10 10 µm 10 100 pm 100 100 µm 100 100 nm 100 - -

Macro-scale Micro- -scale - Nano-scale - - DNA

tissue Human

Bacterium cell Protein

Human hair Individual Also note from our pictorial representation of scales that the next size range that is smaller than the nano-scale is 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 What’s After Nanotechnology – Is there a ?

No, nothing to build at the pico-scale Nano-Scale

• Lots to build at the nano-scale

• Atoms and are the “legos” in the building

• The creating and using of ‘things’ at the nano-scale, for the benefit of mankind, is nanotechnology “Nanotechnology is the builder’s final frontier.”

Richard Smalley 1996 Nobel Laureate in , Nanotechnology has actually been practiced by humans for over 2000 years 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 they used) The Lycurgus Cup is made from glass containing and silver nanoparticles. The cup is seen in: (a) transmitted light and (b) reflected light.

Paul Mulvaney, Not all That’s Gold Does Glitter, MRS Bulletin, December 2001, pg.’s 1009-1013 We now know that the beautiful stained-glass windows made 1600 years ago by the ancient Irish also used nanotechnology (We just found out because we just learned how to see the nano- particles they used) Armagh, Ireland, AD 444 We now know that beautiful plates made by the Renaissance Italians 500 years ago also used nanotechnology

(We just found out because we just learned how to see the nanoparticles they used also) 16th century Renaissance pottery

Padovani et al. J. Appl. Phys. 2003 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 can controllably and repeatedly make things in the nano-scale range • 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! The following picture is a cross-section of an actual man-made (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 (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 (STM) Quantum Corral

M.F. Crommie, C.P. Lutz, D.M. Eigler. Confinement of electrons to quantum corrals on a surface. Science 262, 218-220 (1993). • Because of the advances that have very recently been achieved in what we can make and what we can see, nanotechnology is now manufacturable. That is, nanotechnology can now produce things in huge numbers and economically--not just a few cups, windows, and plates for the very rich, as before

• Because nanotechnology is now manufacturable, it can make products that will affect every man, woman, and child on the planet Key Ideas

• 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 (continued)

• 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