TWO DIMENSIONAL FORM OF CARBON – GRAPHENESupervised By: Submitted By:Prof. Gursharan Kaur Robin Saini M.Sc.4th (Sem.) Physics Roll No. 8057
DEPARTMENT OF PHYSICS KHALSA COLLEGE, AMRITSAR CERTIFICATEThis is to certify that robin saini has completed assignment on“TWO DIMENSIONAL FOM OF CARBON – GRAPHENE’’ and hasSubmitted to P.G Department of Physics , Khalsa College, AmritsarAffiliates to Guru Nanak Dev University , Amritsar under mySupervision . 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 OFNANOTECHNOLOGY:-The idea of manipulating things atom by atom wasgiven 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 composedof one or more nanocomponents. Nanomaterials can be nanoscale in 1 dimension , 2dimension, 3 dimension. They can exist in single, fused, aggregated form withspherical, tabular & irregular shapes.Egs – Nanotubes , buckyball.TYPES OF NANOMATERIALS1.Carbon based materials:- These nanomaterials are composed mostly ofcarbon, most commonly taking the form of hollow spheres, ellipsoids or tubes.Spherical or ellipsoidal carbon nanomaterials are referred to as fullerenes, whilecylindrical ones are called nanotubes2.Metal based materials:- These nanomaterials include quantumdots, nanogold, nanosilver and metal oxides such as titanium oxides. A quantum dotis a closely packed semi-conductor
3.Dendrimers: These nanomaterials are nanosized polymers built frombranched 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 othernanoparticles 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 CARBONAs 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 interestinghistory in many areas of chemistry, physics and engineering.History/ Discovery of Graphene : In 2004, a group of physicists of ManchesterUniversity, UK, led by Andre Geim and Kostya Novoselov used three-dimensional graphitefor their experiment and extracted a single sheet of graphite and simply stuck a flake ofgraphite debris onto plastic adhesive tape, folded the sticky side of the tape over the flakeand then pulled the tape apart cleaving the flake in two. As the process is repeated, theresulting fragment grew thinner. Once the investigators have many thin fragments, theyexamined 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 AHEADThe study of graphene is "very challenging and fascinatingtopic both theoretically and experimentally in condensedmatter physics as well as quantum field theory. Manyphysicists are working in this field. Some new results maycome in the 1st half of this 21st century. THANK YOU