Nanotechnology SUWARNA DATAR| AP 608

Whats going on at nanoscale?

What is unique about this size?

At nanoscale the most fundamental properties of materials depend

on their size which is not true in microscale

Eg. Nnaoscale circuit may not obey Ohm’s law.

This coupling of size with the most fundamental chemical, electrical

and physical properties of materials is the key to nanosceince

What happens when we reduce

the size? Imagine cube of gold with 91.4 cm each side

Produce 8 little cubes from this 50 cm on each side

Properties of each small cube are same as the big

one

Go on reducing this size from 50 cm to 25 cm to

mm to µm, gold will have the same properties

But at nanoscale all the properties like colour,

melting point, chemical properties changes

For every size the colour would be different

History

Every once in a while anything new which is discovered changes

everything

Smaller, lighter, faster and smarter

became the anthem

Nanotechnology now promises to give is everything:

Faster and tinier computers

Better tennis balls

Stain resistant clothing

Transparent sunscreen

Molecular sensors

Cell specific cancer therapy

Plenty of room at the bottom

Scanning Probe Microscopy

1981 1989

Fullerene

The C60 molecule, is 0.7 nm in diameter and,

just like a soccer ball, consists of 20 six-

membered and 12 five-membered rings

In chemistry there is no other molecule which is

formed by same atom and which is as big as

Fullerene

What is Nanoscience &

Nanotechnology

Nanosceince: Study of fundamental principles of molecules and

structures with atleast one dimension roughly between 1 and 100

nm.

Nanotechnology: Applications of these structures into useful devices.

Why is it unique?

Because at this size the regular properties of materials like conductivity,

hardness, melting point etc changes

Emerging Technologies

Fast burning rocket fuel additives

Targeted drug delivery

Detectors for biotoxins

Emerging Technologies

Course structure Introduction : Concept of Length Scales, Definition of Nanotechnology and Nanoscience, Basic

Concepts- Size Effects on Properties, Top Down vs Bottom Up, History of Nanotechnology

Background preparation: Physical Chemistry of solid surfaces, crystal structures, surface energy, chemical potential, Fundamentals of nucleation and growth, Electrostatic Stabilization Surface charge density, Electric potential at the proximity of solid surface, Van der Waals attraction potential, Interactions between two particles: DLVO theory, Solvent and polymer, Interactions between polymer layers, Mixed steric and electric interactions.

Characteristic scale for Nanoscale Phenomenon phenomena: Nanoparticles, nano-clusters, nanotubes, nanowires and nanodots. Electronic structure: quantum dots, quantum wires and quantum wells, confinement of electrons energy quantization semiconductor nanocrystals, carbon nanotubes, quantum wells.

Characterization and properties of nanomaterials: Structural Characterization, X-ray diffraction (XRD), Small angle X-ray scattering (SAXS), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Scanning probe microscopy (SPM), Surface plasmon resonance, Quantum size effects, Surface scattering, Change of electronic structure, Quantum transport, Effect of microstructure, Ferroelectrics and dielectrics, Superparamagnetism.

Applications of Nanomaterials: Molecular Electronics and Nanoelectronics, Biological Applications of Nanoparticles, Catalysis by Gold Nanoparticles, Band Gap Engineered Quantum Devices, Quantum well devices, Quantum dot devices, Nanomechanics, Carbon Nanotube Emitters, Photoelectrochemical Cells.