TWO DIMENSIONAL FORM OF CARBON – GRAPHENE

Supervised By: Submitted By:

Prof. Gursharan Kaur Robin Saini

M.Sc.4th (Sem.) Physics

Roll No. 8057

DEPARTMENT OF PHYSICS

KHALSA COLLEGE, AMRITSAR

CERTIFICATE

This is to certify that robin saini has completed assignment on

“TWO DIMENSIONAL FOM OF CARBON – GRAPHENE’’ and has

Submitted to P.G Department of Physics , Khalsa College, Amritsar

Affiliates to Guru Nanak Dev University , Amritsar under my Supervision .

Prof. Gursharan Kaur

P.G Department of Physics

Khalsa College Amritsar

NANOTECHNOLOGY :- 21st century is the world of research & technology.

Nanotechnology is one of the newly emerging technology .

which includes the study of manipulating matter on an atomic and molecular scale. Generally, it deals with materials or structure possessing atleast one dimension of the size range

1-100 nm

A very Small scale of 10-9 m (1nm) to 10-7 m (100nm) known as nanoscale and it is used for the measurement of nanotechnology materials. A nanometer is one billionth of a meter.

THE BASIC DEFINITION :- Nanotechnology is the engineering of functional system at the molecular scale.

RICHARD FEYNMAN’S IDEA OF NANOTECHNOLOGY:-

The idea of manipulating things atom by atom was

given by Richard Feynman.

He said, “ I want to build a billon tiny factories, models of each other, which are manufacturing simultaneously ….. The principles of physics, as for as I can see, do not speak against the possibility of maneuvering things atom by atom. It is not an attempt to violate any laws; it is something, in principles, that can be done; but in practice, it has not been done because we are too big – Richard Feynman, Nobel prize winner in physics.

NANOMATERIALS:- Nanomaterials are the materials which are composed of one or more nanocomponents. Nanomaterials can be nanoscale in 1 dimension , 2 dimension, 3 dimension. They can exist in single, fused, aggregated form with spherical, tabular & irregular shapes.

Egs – Nanotubes , buckyball.

TYPES OF NANOMATERIALS

1.Carbon based materials:- These nanomaterials are composed mostly of carbon, most commonly taking the form of hollow spheres, ellipsoids or tubes. Spherical or ellipsoidal carbon nanomaterials are referred to as fullerenes, while cylindrical ones are called nanotubes

2.Metal based materials:- These nanomaterials include quantum dots, nanogold, nanosilver and metal oxides such as titanium oxides. A quantum dot is a closely packed semi-conductor

3.Dendrimers: These nanomaterials are nanosized polymers built from branched units. The surface of a dendrimers has numerous chain ends. This property could also be for use for catalysis.

4.Composites: Composites combine nanoparticles with other nanoparticles or with larger bulk type materials.

PROPERTIES OF NANOMATERIALS:

They are hard.They are ductile. They are wear resistant. They are erosion resistant.They are corrosion resistant.

GRAPHENE - TWO DIMENSIONAL FORM OF CARBON As we studied earlier, Nanomaterials can be 1D,2D and 3D.In 2D Nanomaterials, we have various examples and one of them is “Graphene”

“Graphene” – a term derives from the Greek word and has a long and interesting history in many areas of chemistry, physics and engineering.

History/ Discovery of Graphene : In 2004, a group of physicists of Manchester University, UK, led by Andre Geim and Kostya Novoselov used three-dimensional graphite for their experiment and extracted a single sheet of graphite and simply stuck a flake of graphite debris onto plastic adhesive tape, folded the sticky side of the tape over the flake and then pulled the tape apart cleaving the flake in two. As the process is repeated, the resulting fragment grew thinner. Once the investigators have many thin fragments, they examined that pieces and were astonished to find that some were one-atom thick. Graphene was discovered

IMPORTANT POINTS ABOUT GRAPHENE :-

The term Graphene derived from “Greek word”. It is a monolayer of carbon atoms that are arranged in plannar and hexagonal form

Its structure is one – atom thick planar sheets of sp2 - bonded carbon atom that are densly packed in honey – comb crystal lattice.

Graphene is optically transparent, chemically inert and an excellent conductor.

There is a common belief that 2D crystal cannot exist, graphene, a 2D – crystal not only exists but it is extremely strong and stiff.

The cost of graphene with a sample smaller than the thickness of a human hair is more than 1,000 (as in April 2008).

PROPERTIES OF GRAPHENE:

Graphene has high mobility at room temperature. Graphene has a minimum electrical conductivity. Graphene is very strong and rigid. Graphene sheets are held together by vander walls

forces. Graphene has high mechanical thermal properties

APPLICATIONS

Transistors: Graphene can be used to make excellent transistors. Electrons in graphene travel ballistically over sub-micron distances. As a result, graphene-based transistors can run at higher frequencies and more efficiently than in silicon transistors

Gas sensors: Gas molecules that land on graphene affect its

electronic properties in a measurable way. This means that we can create gas sensors which are sensitive to a single atom or molecule.

Inert coatings: Graphene is resistant to acids and alkalis such as ammonia. So it could be used to give objects an atomically thin protective coating which would provide protection against these agents.

Molecular sieves: The open honeycomb structure of graphene means enable atoms and small molecules. It could therefore be used in a way analogous to a filter paper, trapping large molecule and allowing smaller ones to pass.

FUTURE AHEAD

The study of graphene is "very challenging and fascinating topic both theoretically and experimentally in condensed matter physics as well as quantum field theory. Many physicists are working in this field. Some new results may come in the 1st half of this 21st century.

THANK YOU