Transcript GrapheneJohnsonAndPeltier

Graphene
Graphene physically acts as a 2-Dimensional material. This
leads to many properties that are electrially beneficial, such
as high electron moblity and lowered power usage. Graphene
is currently in its infant stages and is undergoing many
applications and studies.
Jared Johnson & Jason Peltier
April 30th
Introduction
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What is Graphene
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Discovery
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Electrical Properties
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Mechanical Strength
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Optical Properties
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Applications
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Devices
What is Graphene
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2-dimensional, crystalline
allotrope of carbon
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Allotrope: property of
chemical elements to exist
in two or more forms
Single layer of graphite
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Honeycomb (hexagonal)
lattice
http://upload.wikimedia.org/wikipedia/commons/thumb/9/9e/Graphen.jpg/750px-Graphen.jpg
Graphene vs Other Allotropes
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Graphene - Top Left
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Graphite - Top Right
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Nanotube - Bottom Left
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Fullerene - Bottom Right
http://graphene.nus.edu.sg/content/graphene
Discovery
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Studies on graphite layers for
past hundred years
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Graphene theory first explored
by P.R. Wallce (1947)
http://powerlisting.wikia.com/wiki/File:Graphite.jpg
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Andre Geim & Kontantin
Novoselov Nobel Peace Prize
(2010)
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Physics observed using TEM
http://www.telegraph.co.uk/science/science-news/8043355/Nobel-Prize-forPhysics-won-by-Andre-Geim-and-Konstantin-Novoselov.html
Electronic Structure
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First Brillouin Zone (red)
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Second Brillouin Zone
(yellow)
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Six corners of first Brillouin
zone called Dirac points (also
called K points)
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Electrons and holes called
Dirac fermions
http://www.doitpoms.ac.uk/tlplib/brillouin_zones/zone_construction.php
Electronic Structure
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Dirac Points are the transition between
the valence band and the conduction
band
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The six Dirac points can be divided into
to two in-equivalent sets of three (K and
K'), represented by the black and white dots on
part (a)
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The points within each set are all
equivalent because they can reach
each other by reciprocal lattice vectors
Part (b) shows that the dispersion
relation close to the K points looks like
the energy spectrum of massless Dirac
particles
http://ej.iop.org/images/0034-4885/75/5/056501/Full/rpp342429f06_online.jpg
Electrical Properties
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The Fermi level can be changed by
doping to create a material that is better
at conducting electricity
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Experimental graphene's electron
mobility is 15,000 cm2/(V*s) and
theoretically potential limits of 200,000
cm2/(V*s)
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Graphene electrons are like photons in
mobility due to lack of effective electron
and hole mass
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These charge carriers are able to travel
sub-micrometer distances without
scattering
Mechanical Strengths
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Bond length is .142 nm long = very strong bond
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Strongest material ever discovered
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ultimate tensile strength of 130 gigapascals compared to 400
megapascals for structural steel
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Very light at 0.77 milligrams per square metre, paper is 1000 times
heavier
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Single sheet of graphene can cover a whole football field while
weighing under 1 gram
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Also, graphene is very flexible, yet brittle (preventing structural use)
Optical Properties
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Absorbs 2.3% white light
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Optical electronics absorb
<10% white light
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Highly conductive
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Strong and flexible
http://en.wikipedia.org/wiki/File:Graphene_visible.jpg
Photograph of graphene in
transmitted light.
Other Applications
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OLED Techonologies
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Body Armour
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Lightweight Aircraft/vehicles
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Photovoltaics
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Superconductor/battery
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Filtration
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http://www.graphenea.com/pages/graphene-uses-applications#.U1c1hFVdV8E
Devices
http://www.tgdaily.com/general-sciences-features/61058-team-uses-graphene-film-to-distil-vodka
http://www.simplifysimple.com/index.php?news&nid=15_The-new-look-of-phones
http://en.wikipedia.org/wiki/OLED
Summary & Conclusion
Graphene, a singular layer of graphite, has been
discovered to have unique properties. The high
mobility and ability to travel short distances without
scattering makes it one of the best materials for
electrical applications. Graphene's mechanical and
optical properties also allow its use to go beyond
electrical applications.
References
1. "Allotrope." Wikipedia. Wikimedia Foundation, 16 Apr. 2014. Web. 17 Apr. 2014.
<http://en.wikipedia.org/wiki/Allotrope>.
2. Cooper, Daniel R. "Experimental Review of Graphene." Hindawi Publishing Corporation, 3 Nov.
2011. Web. 16 Apr. 2014. <http://www.hindawi.com/journals/isrn/2012/501686/>.
3. De La Fuente, Jesus. "Graphene." Graphenea. Web. 26 Apr. 2014.
<http://www.graphenea.com/pages/graphene#.U1xxufldWSo>.
4. Geim, Andre. "Nobel Lecture." Nobel Prize, 8 Dec. 2010. Web. 18 Apr. 2014.
<http://www.nobelprize.org/mediaplayer/index.php?id=1418>.
5. "Graphene." Wikipedia. Wikimedia Foundation, 16 Apr. 2014. Web. 17 Apr. 2014.
<http://en.wikipedia.org/wiki/graphene>.
6. Neamen, Donald A. Semiconductor Physics and Devices: Basic Principles. New York, NY:
McGraw-Hill, 2012. Print.
7. Roos, Michael. "Intermolecular vs Molecule–substrate Interactions." Beilstein Journal of
Nanotechnology 2012.2, 365-73. Web. 15 Apr. 2014. <http://www.beilsteinjournals.org/bjnano/single/articleFullText.htm?publicId=2190-4286-2-42>.
8. "Graphene." NUS Graphene Research Centre. National University of Singapore, n.d. Web. 28 Apr.
2014. <http://graphene.nus.edu.sg/content/graphene>.
Last Slide
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Graphite had been studied for over a hundred years but Geim and
Novoselov found how to isolate it to be graphene and some
applications for its use
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The reason graphene is such a beneficial material is due to its 2D
like nature and short/strong bonds
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It has a super high conductivity and an electron mobility of
15,000 cm2/(V*s)
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It is the strongest material ever discovered, however its brittle
nature cannot be used structurally (only to help reinforce)
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One of the most common current uses of graphene is in OLEDs