Introduction To Nanotechnology

A Presentation By-A. S. Kurhekar

http/sites.google.com/site/anilkurhekar100/

Agenda What is nanotechnology and why is it

important? Some history and characterization

techniques Examples of nanomaterials, research,

applications, and emerging trends Introductions Final (opening) motivation and advice

Definition Nanotechnology is the ability to understand, control,

and manipulate matter at the level of individual atoms and molecules as well as at the “supramolecular level” involving clusters of molecules, in order to create materials, devices, and systems with fundamentally new properties and functions because of their small structure. The definition implies using the same principles and tools to establish a unifying platform for science and engineering at the nanoscale, and employing the atomic and molecular interactions to develop efficient manufacturing method

National Science Foundation (NSF)National Nanotechnology Initiative (NNI)

How big a nanometer is ?

Beneath 1 millimeter

Opportunity

Need: education

A key challenge for nanotechnology development is the education and

training of a new generation of skilled workers in the multidisciplinary

perspective necessary for rapid progress of the new technology. Theconcept at the nanoscale (atomic, molecular and supra-molecularlevels) should penetrate the education system in the next decade in asimilar manner to how the microscopic approach made inroads in thelast forty to fifty years…It is estimated that about 2 million nanotechnology workers will beneeded worldwide in 10-15 years.

0.8 million in US 0.5 – 0.6 million in Japan 0.3-0.4 million in Europe 0.1-0.2 million in Asia/Pacific region excluding Japan and more in other regions.

Nano-manufacturing Realize the breadth and accelerating pace of nanotechnology

and the imperative for nano-manufacturing Understand the fundamental properties of nanostructures,

e.g., nano-particles, nano-tubes, and nano-wires Understand how nanostructures interact with one another and

the surrounding medium …the physics of interactions Understand how to make nanostructures Understand how to assemble nanostructures, e.g., top-down

vs. bottom-up, 1D, 2D, and 3D Understand how the properties of nanostructures scale with

assembly methods, and how interactions govern suprananoscaleproperties

Nano-manufacturing Goal

Learn how to design and manufacture new materials and devices by harnessing the special properties and interactions of nanostructures

Enhance our ability to define important research questions, critically judge their validity based on fundamental principles, and design experiments to answer these questions

Nanomaterials are not “New”

It is probable that “soluble” gold appeared around the 5th or 4th century B.C. in Egypt and China.

The Lycurgus Cup that was manufactured in the 5th to 4th century B.C. It is ruby red in transmitted light and green in reflected light, due to the presence of gold colloids.

In 1857, Faraday reported the formation of deep red solutions of colloidal gold by reduction of an aqueous solution of chloroaurate (AuCl4) using phosphorus in CS2(a two-phase system) in a well known work.

Faraday investigated the optical properties of thin films prepared from dried colloidal solutions and observed reversible color changes of the films upon mechanical compression (from bluish-purple to green upon pressurizing).

Ability to be nanoscientists is new

So, nanomaterials are definitely not new!

but our ability to be nanoscientists is new, because we’ve created instruments and machines for controlled characterization and fabrication

these enable nanotechnology

The Electron Microscope

Goodhew, Microscopy and Microanalysis

Scanning probe microscopes

invented by Young and colleagues, NIST, 1972 Binnig and Rohrer, Nobel Prize, 1986

Binnig, Quate, Gerber, 1986

Scanning tunneling microscope (STM)

Atomic force microscope (AFM)

Nano-scale

Nanotube on a scanning probe tip

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

About 25 nanometers

Current resolution limits approach visibility of individual atoms and defects

Building blocks

Nanoclusters / NanoparticlesMagic #’s of atoms 100s-1000s of atoms≤1 nm size ~1-100 nm diameter

Nanowires / NanotubesFilled Hollow~1-100 nm dia, up to mm long and beyond!

Semiconducting Nanocrystals:“Quantum Dots”

photo by F. Frankel, MIT

Hodes, Advanced Materials, 19:639, 2007.

<100> CdSe <001> CdSe

Nanowire chemical sensors

- Molecule-sized binding sites = high S/N-Engineer binding to be molecule-Specific Arrays can be multiplexed to detect lots of markersPatolsky and Lieber, Materials Today,2007.

Principle of carrier injection

CNT Based Memory

Reversible electromechanical junction

Rueckes et al, Science 289, 2000; http://www.nantero.com

Nanogold Well… strange things happen at

the small scale If you keep cutting until the

gold pieces are in the nanoscale range, they don’t look gold anymore… They look RED!

In fact, depending on size, they can turn red, blue, yellow, and other colors

Different thicknesses of materials reflect and absorb light differently

12 nm gold particles look red

Other sizes are other colors

Fabrication Methods

Atom-by-atom assembly Like brick-laying, move atoms

into place one at a time using tools like the AFM and STM

Chisel away atoms Like a sculptor, chisel out

material from a surface until the desired structure emerges

Self assembly Set up an environment so atoms

assemble automatically. Nature uses self assembly (e.g., cell membranes)

IBM logo assembled from individual xenon atoms

Polystyrene spheres self-assembling

Example: Self Assembly By Crystal Growth

Grow nanotubes like trees Put iron nanopowder crystals on a

silicon surface Put in a chamber Add natural gas with carbon (vapor

deposition) Carbon reacts with iron and forms a

precipitate of carbon that grows up and out

Because of the large number of structures you can create quickly, self-assembly is the most important fabrication technique

Growing a forest of nanotubes!

An SiO2 Micro-cantilever

Collaborate and learn from others

“The thing I want to say is collaborate. Collaborating withtalented people is not easy, but it’s the way to really shine – youshine brighter if you are working with really great people. Theimportant thing in the end is not that you are proved right everytime, the important thing is that the music is the best that it canbe. I want to wish you all that you would find your own voice.But if you are so disposed that you would find collaborators towork with, that you would shine as you could never shine onyour own.”

Dave “The Edge” Evans (U2), at Berklee College of MusicCommencement, Boston, MA, May 2007.

A Quiz !!!1. How big is a nanometer compared to a meter? List one

object that is nanosized, one that is smaller, and one that is larger but still not visible to the naked eye.

2. Name two properties that can differ for nanosized objects and much larger objects of the same substance. For each property, give a specific example.

3. Describe two reasons why properties of nanosized objects are sometimes different than those of the same substance at the bulk scale.

4. What do we mean when we talk about “seeing” at the nanoscale?

5. Choose one technology for seeing at the nanoscale and briefly explain how it works.

6. Describe one application (or potential application) of nanoscience and its possible effects on society.

Thank You.