Nanophysics

Nanophysics
Guidance by:-
Mr. Goverdhan
Yadu
Submitted by:-
Rahul Sahu
M.Sc.- Physics 3rd
Sem

Contents:-
 Nanophysics
 Nano Material
 Classification
 Example
 Synthesis
 Application

What is Nanophysics?
 Nanophysics is a physics which is applied at
nanometer range. In nano range properties of
materials are changed. Basically at nano range the
surface properties of materials start dominating
compare to bulk properties. In surface there are
dangling bond which have high surface energy
compared to bulk.
 1 nanometer is equal to one billionth of meter,
1 nm= 1/1000000000 meters or 10-9 meters.

Nano Material
 Nano Materials could be defined as the materials with
at least one of its dimensions in the range of nano
meter.
 Thus the material need not be so small that it cannot
be seen, it can be a large surface or a long wire whose
thickness is in the scale of nano meters.
 Materials of which a single unit is sized (in at least
one dimension) between 1 to
1000 nanometers (10−9 meter) but usually is 1 to
100 nm.

Classification Of Nano Materials
Classification is based on the number of dimensions ,
which are not confined to the nanoscale range (<100
nm).
(1). Zero-Dimensional Nano Materials-
 Materials wherein all the dimensions are measured
within the nanoscale which means all three dimensions
are in the range of 1 to 100 nm.
 Most common representation of zero-dimensional
nano materials are nanoparticles .
Ex- Quantum Dots

(2). One-Dimensional Nano Materials-
 In this type of nonmaterial, one of dimension that is
outside of nanoscale. One dimensional nanomaterial
has contain needle shaped nanomaterial.
 It is include Nanorods ,Nanowires etc.
Ex – Carbon Nanotubes
(3). Two-Dimensional Nano Materials-
 In this type of nanomaterial, two of the dimensions
are not confined to the nanoscale.
 It is include Nanocoating, Nanolayers etc.
Ex - Nanofilms

(4). Three-Dimensional Nano Materials-
 Bulk nanomaterials are materials that are not confined
to the nanoscale in any dimension. These materials are
thus characterized by having three arbitrarily
dimensions above 100 nm.
Materials possess a nanocrystalline structure or involve
the presence of features at the nanoscale. In terms of
nanocrystalline structure, bulk nanomaterials can be
composed of a multiple arrangement of nanosize crystals
most typically in different orientations.
With respect to presence of features at the nanoscale, 3-D
Nanomaterials can contain dispersions of nanoparticles,
bundles of nanowires and nanotubes as well as
multinanolayers.
Ex - Graphite

Quantum dots
A quantum dot is a nanoparticle made of any
semiconductor material such as silicon, cadmium
selenide, cadmium sulfide, or indium arsenide.
Quantum dot has larger bandgap. A quantum dot gets
its name because it's a tiny speck of matter so small that
it's effectively concentrated into a single point (in other
words, it's zero-dimensional)

Carbon Nanotubes
If we take CNTs(Carbon Nanotubes) then we can seen
that it is long, thin cylinders of carbon. They can be
thought of as a sheet of graphite (a hexagonal lattice of
carbon ) rolled into a cylinder. Nanotubes have been
constructed with length –to-diameter ratio of up to
132,000,000 : 1.
It has two type – (a) Single-walled carbon nanotube
(b) Multi-walled carbon nanotube

Nanofilms
A thin film is a layer of material ranging from fractions of
a nanometer (monolayer) to several micrometers in thickness. A familiar
example is the household mirror, which typically has a thin metal coating
on the back of a sheet of glass to form a reflective interface. The process
of silvering was once commonly used to produce mirrors, while more
recently the metal layer is deposited using techniques such as sputtering.
It is also being applied to pharmaceuticals, via thin-film drug delivery. A
stack of thin films is called a multilayer.

Graphite
Layer structure with strong bonding within the planar
layers and weak, vander-waals bonding between layers.
It is good electrical conductor. Chemically stable even at
high temperatures . It is a layered compound. In each
layer, the carbon atoms are arranged in a hexagonal
lattice with separation of 0.142 nm and the distance
between planes is 0.335 nm.

Synthesis
There are two approaches for synthesis of nanomaterials–
(1) Top - Down approach:-
 This is a technique in which materials and devices are
synthesized or constructed by removing existing
material from larger entities.
 Top down approach refers to slicing or successive
cutting of a bulk material to get nano sized particle. In
this approach the starting material is solid state.
Deposition over a large substrate is possible. Chemical
purification is not required.
 Control over deposition parameters is difficult to
achieve. Varied particle shapes or geometry.

(2) Bottom – Up approach
 This is a technique in which materials and devices are
built up atom by atom i.e. a technique to collect,
consolidate and fashion individual atoms and
molecules into the structure.
 Atom by atom deposition leads to formation of self –
assembly of atoms/molecules and clusters.
 These clusters come together to form self - assembled
monolayer on the surface of substrate.
 All the bottom-up techniques, the starting material is
either gaseous state or liquid state of matter.
 In this approach the deposition parameters can be
controlled .
 Large scale production is difficult and chemical
purification of nanoparticles is required.

Top – Down Bottom – Up
Atoms
Clusters

Applications
 Medicine
 Computers
 Electronics
 Textile
 Military

Nanophysics

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