1 GRAPHENE NANORIBBONS
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1 GRAPHENE NANORIBBONS USC Department of Physics Graduate Seminar Nahid Shayesteh,
Transcript of 1 GRAPHENE NANORIBBONS
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GRAPHENE NANORIBBONS
USC Department of Physics Graduate Seminar
Nahid Shayesteh,
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Carbon based material
Discovery and innovation of graphen
Graphene nanoribbons structure
Application of Graphene nanoribbons
Outlines…
Nahid Shayesteh, Department of Physics
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Carbon-based nanoelectronics….
1. Replace silicon-based micro electronics.
2. Exhibit superior physical properties in many aspects.
3. Industrial applications
FUNCTIONS…
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The term graphene
1962—Hanns-Peter Boehm coined graphene as a combination of graphite and the suffix –ene to describe single-layer carbon foils.
Hanns-Peter Boehm: Born January 9, 1928 in Paris German Chemist
Professor Emeritus in Ludwig-Maximillians University in Munich,Germany
Pioneer of graphene research
History…
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Mitsutaka Fujita (藤田 光孝 Fujita Mitsutaka)
Introduced graphene nanoribbons as a theory model to examine the edge and nanoscale size effect in graphene.
Japanese Physicist
Born: August 16, 1959
Died: March 18, 1998
Innovation…
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Definition: thin strips of graphene
Graphene nanoribbons
GNR’s
Nano-graphene ribbons
Terminology…
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The structure of Graphene consists of… Honeycomb Lattice
2 Dimension thin layer of
Carbon atoms
Basic structure of
carbon hexagon of
graphene
Lattice Structure …
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The carbon-carbon bond length in graphene is about 0.142 nanometers.
Graphene sheets stack to form graphite.
One stack of 3 million sheets = 1 millimeter thick.
Graphene is the basic structural element of some carbon allotropes including…
Graphite
Charcoal
Carbon Nanotubes
Fullerence
Chemical Structures…
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The Energy gap of the 1 dimensional graphene nanoribbons (GNRs), can be… Produced lithographically by patterning 2 dimensional
graphene through a chemical route
Different crystallographic orientations
Tuned with varying widths
Energy Gap…
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Graphene projections…
Display hopeful electronic properties.
(as a conductor of electricity as well as cooper and as a conductor of heat better than all other known materials)
Possess very high electron or hole mobility
(comparable to the properties observed in Carbon nano tubs)
Longest measured mean-free path
High optical transmission
(optical transmission and infrared reflectivity can be tuned as a function of the applied voltage)
In theory…
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Graphene is considered a semimetal, because…
There is no present band gap (band gap is zero).
There is a narrow channel width (transverse direction) & a
band gap can be provided.
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Graphenenanoribons (GNRs) can be obtained by unzipping the single wall carbon nanotubes.
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The ribbon form of graphene (GNR) Inherited almost all of the attractive properties of the carbon nanotube
and graphene.
Additional benefit of a tunable band gap.
Tunable semiconducting behaviors vis a vis changing ribbon width.
The first bandgap measurements are made by... Phaedon Avouris.
Philip Kim
Opening of energy gaps… Reported: 0.5 eV in a 2.5 nm wide armchair ribbon
Electronic Properties…
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Zigzag & Armchair GNRs are metallic or semiconducting electronic properties that depends on the width of the nanoribbon.
Electronic properties depend on…
the edge shape
1. armchair
2. zigzag
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Electronic Properties…
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Liang work shows certain armchair GNRs can display semiconducting behavior.
Armchair ribbon is semiconducting when N=3p or
N=3p+1
#of dimer lines N=3p+2 is semimetal behavior
(p is integer).
Armchair GNR’s…
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Zigzag GNRs are either…
1. Semiconducting
2. Metallic
And
Expected to be more conductive
Zigzag GNR’s…
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In transparent
Conductive electrodes
In liquid crystals
Solar cell systems
Light emitting diodes
P-N junctions
Schotkky diodes
Field effect transistors
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Applications…
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A p–n junction is formed at the boundary between a p-typeeand n-type semiconductor-type created in a single crystal of semiconductor by doping.
A Schotkky is a special case of a p–n junction, where metal serves the role of the n-type semiconductor.
Nahid Shayesteh, Department of Physics
Junctions…
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A transistor is a semiconductor device used to amplify and switch electronic signals and power.
The field-effect transistor (FET) is a transistor that relies on an electric field to control the conductivity of a channel of one type of charge carrier in a semiconductor material.
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Transistors…
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New types of the graphene base material can be achieved.
Carbon based material have different application depend on their structure.
Conclusion…
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References…
1.Bu, H., et al., Atomistic simulations of mechanical properties of
graphene nanoribbons. Physics Letters A, 2009. 373(37): p. 3359-3362.
2.Eduardo V Castro1, N.M.R.P., J M B Lopes dos Santos1, and
F.G.a.A.H.C. Neto4, Bilayer graphene: gap tunability and edge
properties. Journal of Physics, 2010. 129(1): p. 012002(8).
3.connor, O., Liu,, CNTFET Modeling and Recongurable Logic-Circuit
Design. Ieee Transactions on Circuits and Systems, 2007. 54(11): p.
2365-2379.
4.Group, C.M., Moore' s Law: More or Less. www.
cmg.org/measureits/issues/mit41/m_41 2.html, 2010.
5.Novoselov, K.S., Electronic properties of graphene. phys. stat. sol. ,
2007. 244(11 / DOI 10.1002/pssb.200776208): p. 4106-4111.
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Thank you for your time and
consideration. I will be more than happy to answer any questions or concerns that you may have at this
time.
