Nanotechnology Basics (HS)

David T. Shaw

State University of New York at Buffalo

What is Nanotechnology?

WHAT DOES NANOTECHNOLOGY

MEAN TO YOU?

• The study of objects and phenomena at a very small scale, roughly 1 to 100 nanometers (nm)

– 10 hydrogen atoms lined up measure about 1 nm– A grain of sand is 1 million nm, or 1 millimeter, wide

• What’s interesting about the nanoscale?– Nanosized particles exhibit different properties than larger

particles of the same substance

• Studying phenomena at this scale will… – Change our understanding of matter– Lead to new questions and answers in many areas, like health care, energy, technology

What is Nanotecnology?

3

How Small is Nanometer?

1 nm = 10-9 meter

How Small is Nanometer?

What’s So Special About Nano?

• Using new scientific tools, we have found that nano- sized particles of a given substance exhibit different properties than larger particles of the same

substance• As we study these materials at the nanoscale, we are

– Learning more about the nature of matter– Developing new theories– Learning how to manipulate their properties to develop new

products and technologies

Painting On Solar Cells

• Nano solar cells mixed in plastic could be painted on buses, roofs, clothing – Solar becomes a cheap energy alternative!

http://www.berkeley.edu/news/media/releases/2002/03/28_solar.html

Inorganic nanorods embedded in semiconducting polymer -- sandwiched between two electrodes

History of Nanotechnology

Some have argued that nanoscience started billions year ago, when the first living cells emerge. Cells house nanoscale biomachines perform such tasks as manipulating genetic

materials and supplying energy.

Dunin-Borkowski Science (98)

Natural chains of Natural chains of magnetic nano-crystals magnetic nano-crystals in bacteriain bacteria

“There’s Plenty of Room at the Bottom”

Most, however, consider Richard Feynman’s famed talk in1959 as a historical moment for nanoscale

science and technology

The accuracy of Feynman’s vision is breath-taking. A few of his predictions include: •electron and ion beam fabrication,•molecular beam epitaxy, •nanoimprint lithography, •scanning tunneling microscopy, •single electron transistors, •spin electronics, and •nanoelectromechanical systems (NEMS).

To read the entire Feynman’s classic paper, please Click

Genesis of Nanotechnology

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New Tools

As tools change, what we can see and do

changes

Light microscope(magnification up to 1000x)

to see red blood cells (400x)

Sources: http://www.cambridge.edu.au/education/PracticeITBook2/Microscope.jpg http://news.bbc.co.uk/olmedia/760000/images/_764022_red_blood_cells300.jpg

Using Light to See

• The naked eye can see to about 20 microns• A human hair is about 50-100 microns thick

• Light microscopes let us see to about 1 micron• Bounce light off of surfaces to create images

Greater resolution to see things like blood cells in greater detail

(4000x)

Sources: http://www.biotech.iastate.edu/facilities/BMF/images/SEMFaye1.jpg http://cgee.hamline.edu/see/questions/dp_cycles/cycles_bloodcells_bw.jpg

Using Electrons to See

• Scanning electron microscopes, invented in the 1930s, let us see down to about 10 nanometers• Bounce electrons off of surfaces to create images• Higher resolution due to small size of electrons

Touching the Surface

• Scanning probe

microscopes, develop-ed in the 1980s, give us a new way to “see” at the nanoscale

• We can now see really small things, like atoms, and move them too!

About 25 nanometers

This is about how big atoms are compared with the tip of the

microscopeSource: Scientific American, Sept. 2001

Tools of Nanotechnology

Bright spotselectrons, dark spots holes.

Images of movement of electrons and holes through a semi-conductor substrate

Yoo et al, Science (97)

Development of STM-related techniques greatly accelerates

the progress of nanotechnology

STM Art Gallery

IBM IBM

coronene

OmicronLi, PRL(02)

How Do Properties of Nanostructures Change?

• Properties of a substance depend on:– Size of the aggregation of particles– Surface to volume ratio

• Also, at the nanoscale, some properties such as boiling temperature do not apply– Vapor pressure becomes less and less meaningful

when you have smaller and smaller numbers of particles

– When you have 50 molecules there are no bubbles!

Sources: http://www.bc.pitt.edu/prism/prism-logo.gifhttp://www.physics.umd.edu/lecdem/outreach/QOTW/pics/k3-06.gif

Size-Dependent Properties

• Properties of a material– Describe how the material acts under

certain conditions– Are often measured by looking at large

(~1023) aggregation of atoms or molecules

• Types of properties– Optical (e.g. color, transparency)– Electrical (e.g. conductivity)– Physical (e.g. hardness, boiling point)– Chemical (e.g. reactivity, reaction rates)

Optical Properties Example: Gold

• Bulk gold appears yellow in color• Nanosized gold appears red in color

– The particles are so small that electrons are not free to move about as in bulk gold

– Because this movement is restricted, the particles react differently with light

Sources: http://www.sharps-jewellers.co.uk/rings/images/bien-hccncsq5.jpghttp://www.foresight.org/Conferences/MNT7/Abstracts/Levi/

12 nanometer gold particles look red“Bulk” gold looks yellow

Why Do Properties Change?

• Four important ways in which nanoscale materials may differ from macro scale materials– Gravitational forces become negligible and electromagnetic

forces begin to dominate– Quantum mechanics is used to describe motion and energy

instead of classical mechanics– Greater surface to volume ratios– Random molecular motion becomes more important

Dominance of Electromagnetic Forces

• Because the mass of nanoscale objects is so small, gravity becomes negligible– Gravitational force is a function of mass and is weak

between nanosized particles– Electromagnetic force is not affected by mass, so it can be

very strong even when we have nanosized particles– The electromagnetic force is much more stronger than

gravitational force at nanoscale

Quantum Mechanical Model Needed

• Classical mechanical models explain phenomena well at the macro scale level, but break down at the nano- scale level

• Four phenomena that quantum mechanical models can explain (but classical mechanical models cannot)– Discreteness of energy– The wave-particle duality of light and matter– Quantum tunneling– Uncertainty of measurement

Surface to Volume Ratio Increases

• As surface to volume ratio increases – A greater amount of a substance

comes in contact with surround-ing material

– This results in better catalysts, since a greater proportion ofthe material is exposed for potential reaction

Source: http://www.uwgb.edu/dutchs/GRAPHIC0/GEOMORPH/SurfaceVol0.gif

Source: http://galileo.phys.virginia.edu/classes/109N/ more_stuff/Applets/brownian/brownian.html

Random Molecular Motion is Significant

• Random motion at the macro scale– Small compared the size of the substance– We can barely detect motion of dust particles on the

surface of water

• Random motion at the the nanoscale– Large when compared to the size of the substance– The molecules that make up the dust particle are moving

wildly

• How might new innovations change our lives?– Materials: stain-resistant clothing– Environment: clean energy, clean air– Technology: better data storage and computation– Heathcare: chemical and biological sensors, drugs and

delivery devices

Potential Impact of Nanotechnology

Thin layers of gold are used in tiny medical devices

Carbon nanotubes can domany things!

Possible entry point for nanomedical device

A DVD That Could Hold a Million Movies

• New nanomedia could result in a million times greater storage density

New nanomedia: Gold self-assembles into strips on silicon

(scale is nanometers)Current CD and DVD media

(scale is microns)

Source: http://uw.physics.wisc.edu/~himpsel/nano.html

Building Smaller Devices and Chips

• Nanolithography to create tiny patterns– Lay down “ink” atom by atom

Mona Lisa, 8 microns tall, created by AFM nanolithography

Re: http://www.ntmdt.ru/SPM-Techniques/Principles/Lithographies/AFM_Oxidation_Lithography_mode37.html http://www.chem.northwestern.edu/~mkngrp/dpn.htm

Transporting molecules to a surface by dip-pen nanolithography

Nerve Tissue Talking to Computers

• Neuro-electronic networks interface nerve cells with semiconductors– Possible applications in brain research,

neurocomputation, prosthetics, biosensors

Snail neuron grown on a chip that records the neuron’s activity

Source: http://www.biochem.mpg.de/mnphys/publications/05voefro/abstract.html

Detecting Diseases Earlier

Cancer in Color

Growing Tissue to Repair Hearts

• Growing cardiac muscle tissue is an area of current research– Grown in the lab now, but the fibers

grow in random directions – With the help of nanofiber filaments,

it grows in an orderly way

• Could be used to replace worn out or damaged heart tissue

Source: http://www.washington.edu/admin/finmgmt/annrpt/mcdevitt.htm

Cardiac tissue grown with the help of nanofiber filaments

Sources: http://www.zephyr.dti.ne.jp/~john8tam/main/Library/influenza_site/influenza_virus.jpg http://pubs.acs.org/cen/topstory/8005/8005notw2.html

Influenza virus: Note proteins on outside that bind to cells

Preventing Viruses from Infecting Us

• The proteins on viruses bind to our body cells• Could cover these proteins with nanocoatings

– Stop them from recognizing and binding to our cells– We would never get the flu!

• A protein recognition system has been developed

Gold tethered to the protein shell of a virus

Making Repairs to the Body

• Nanorobots are decades away, but could…– Break apart kidney stones, clear plaque from blood

vessels, ferry drugs to tumor cells

Source: http://www.genomenewsnetwork.org/articles/2004/08/19/nanorobots.php

Summary• An emerging, interdisciplinary Science and technology nano-

scale, integrating chemistry, physics, biology, and earth science with technology

• The power to collect data and manipulate particles at nanoscale will lead to– New areas of research and technology design

– Better understanding of matter and interactions

– New ways to tackle important problems in healthcare, energy, environment, and technology

– A few practical applications now, but most are years or decades away