What is “Nano-scale Science and

Technology”?

Yonhua Tzeng, ProfessorElectrical and Computer Engineering

Auburn University, Alabama USA

July 7, 2003

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End Cap

The EarthSoccer Ball

STM Image of C60

STM image of a carbon nanotube

http://www.wtec.org/loyola/nano/IWGN.Public.Brochure/IWGN.Nanotechnology.Brochure.pdf

What is “Nanotechnology”?

http://dynamo.ecn.purdue.edu/~janes/whats_nano.htm

http://dynamo.ecn.purdue.edu/~janes/whats_nano.htm

Nanoparticles have been used in our daily life.

Carbon black ( a nanoscale carbon) is used for writing and painting and

is added to rubber to make tires more wear resistance.

Nano phosphors in CRTs display colors.

Polishing compounds for smoothing silicon wafers include nanoscale alumina and silica, etc.

Hard disks in our computers contain nanoscale iron oxide magnetic particles.

Nanoscale zinc oxide and titania block UV light for sunscreens.

Nanoscale platinum particles are critical to the operation of catalytic converters.

Metallic nanoparticles make stained glass and Greek vase colorful.

Nanoscale thin films have also been the heart of our silicon chips for our computers, digital cameras, and photonic devices for quite a while.

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Commercial TiO2 Nanoparticles

Atoms, Molecules, And Nano-meter

Sized Particles Have Been Around

For A Long,Long Time.

What is new?

What makes it a promising technology?

What is it good for?

http://dynamo.ecn.purdue.edu/~janes/whats_nano.htm

STM probe images of Fe atoms on Cu from IBM Almaden Research Lab

http://www.almaden.ibm.com/vis/stm/atomo.html

http://www-inst.eecs.berkeley.edu/~ee143/f2002/Lectures/Lec_28.pdf

Small, of course!

http://cache.techtv.com/binaries/2002/smallgear.mpg

http://cache.techtv.com/binaries/2002/gearandshaft.mpg

How small? Atomic and Molecular Scales!

Definition of Nanotechnology (i):The following is excerpted from the National Nanotechnology Initiative: The Initiative and its Implementation Plan (http://www.nano.gov/nni2.htm)

The essence of nanotechnology is the ability to work at the molecular level, atom by atom, to create large structures with fundamentally new molecular organization. Compared to the behavior of isolated molecules of about 1 nm (10 -9 m) or of bulk materials,

behavior of structural features in the range of about 10 -9 to 10 -7 m (1 to 100 nm - a typical dimension of 10 nm is 1,000 times smaller than the diameter of a human hair) exhibit important changes. Nanotechnology is concerned with materials and systems whose structures and components exhibit novel and significantly improved physical, chemical, and biological properties, phenomena, and processes due to their nanoscale size.

The goal is to exploit these properties by gaining control of structures and devices at atomic, molecular, and supramolecular levels and to learn to efficiently

manufacture and use these devices. Maintaining the

stability of interfaces and the integration of these "nanostructures" at micron-length and macroscopic scales are all keys to success.

Definition of Nanotechnology (ii):

New behavior at the nanoscale is not necessarily predictable from that observed at large size scales.

The most important changes in behavior are caused not by the order of magnitude size reduction, but by newly observed phenomena intrinsic to or becoming predominant at the nanoscale.

These phenomena include size confinement, predominance of interfacial phenomena and quantum mechanics.

Definition of Nanotechnology (iii):

Once it becomes possible to control feature size, it will also become possible to

enhance material properties and device functions beyond what we currently know how to do or even consider as feasible.

Being able to

reduce the dimensions of structures down to the nanoscale leads to the unique properties of carbon nanotubes, quantum wires and dots, thin films, DNA-based structures, and laser emitters.

Such new forms of materials and devices herald a revolutionary age for science and technology, provided we can discover and fully utilize the underlying principles.

Definition of Nanotechnology (iv):

Fundamental Principles

Nanoscale Phenomena

• Size effects

• Confinement

• Interfacial phenomena

• Quantum mechanics

• Biological systems

Size and Shapes: High aspect ratio of carbon nanotubes and Metal-atom filled Nanotubes

Nanostructure Science : R&D Status and Trends in Nanoparticles, Nanostructured Materials, and Nanodevices (1998) http://www.wtec.org/loyola/pdf/nano.pdf and Technology

Properties of the Carbon Nanotubes

http://www.bit.ac.at/nmp/AT_F_Kooperation/02_hammel.pdf

Molecular Structural Effects

Size Effects

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Image from Prof. Prorok, Auburn University

http://www.physik.uni-wuerzburg.de/TEP/Website/events/ESS_2001/Reithmaier/EU_summer_2001_talk2.pdf

Confinement Effects

http://www.unipress.waw.pl/CE/Network/network.pdf

Confinement Effects