Graphene is a one-atom-thick planar sheet of sp2-bonded carbon atoms that are densely packed in a honeycomb crystal lattice The name ‘graphene’ comes from graphite + -ene = graphene

1. Presentation topic: Graphene Nanoribbons
Presented to: Rethwan Faiz
Course name: Power System Analysis
Section: [G]
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2. Presentation members
Presented by:
2
SL Name I.D
1 Waleed, Khaled bin 14-26027-1
2 Hossen, MD. Saddam 13-24244-2
3 Hossain, MD. Anowar 13-24191-2
4 Mozammel, S. M. Mahmud 14-25942-1

3. Outlines
Graphene
Carbon nanotubes (CNT)
Graphene nanoribbons (GNR)
Comparison between CNT and GNR
Synthesis methods of GNRs
Applications of GNRs
Op amp circuit using CNTFET
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4. Graphene
Graphene is a one-atom-thick planar sheet of sp2-bonded carbon
atoms that are densely packed in a honeycomb crystal lattice
The name ‘graphene’ comes from graphite + -ene = graphene
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Molecular structure of
graphene

5. Properties of Graphene
pure substance, orderly structure based on tight, regular, atomic
bonding
Graphene is believed to be the strongest material yet
discovered
Has high thermal conductivity
Can conduct electricity very well
Is very light and transparent
Sheets of Graphene are impermeable
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Graphene is the basic structural element of some carbon allotropes
including…
 Graphite
 Charcoal
 Carbon Nanotubes
 Fullerene

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Carbon Nanotubes (CNT)
Carbon nanotubes (CNT) are basically graphene sheets rolled
up in a certain direction.
“Chiral vector” or “chirality” describes how a graphene sheet
is rolled up to form CNT.
CNT might be metallic or semiconducting, depending on its
chirality.
Carbon nanotubes are strong, they are not brittle.
They can be bent, and when released, they will spring back to
their original shape.

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Types of Carbon Nanotubes
A carbon nanotube with open ends A carbon nanotube with closed ends

9. Graphene Nanoribbons (GNR)
also called nano-graphite ribbons
carbon based material
one-dimensional structures with hexagonal two dimensional
carbon lattices
a derivative of Graphene
Graphene ribbons were introduced as a theoretical model
by Mitsutaka Fujita
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types of GNR edges

11. Properties of GNR
GNR inherits almost all the attractive properties of the carbon
nanotube and graphene.
Has additional benefit of a tunable band gap
Zigzag & Armchair GNRs have metallic or semiconducting
electronic properties that depends on the width of the
nanoribbon.
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Comparison between CNT and GNR
A CNT Molecular Structure A GNR Molecular Structure

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Comparison between CNT and GNR
A CNT Unit Cell A GNR Unit Cell

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Rolling of a Carbon nanotube (CNT)
from a graphene sheet
Cutting of a graphene
nanoribbon (GNR) from a sheet
of graphene

15. Synthesis methods of GNRs
The structure and physical properties of GNRs vary significantly
depending on the synthesis method. The methods are:
cutting from graphene using lithography
 bottom-up synthesis from polycyclic molecules
unzipping of carbon nanotubes (CNTs)
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16. Applications of GNRs
Light emitting diodes
P-N junctions
Schottky diodes
Field effect transistors
Conductive electrodes
Solar cell systems
Field effect transistors
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Op-Amp internal circuit
Fig 1: Normal material Op Amp

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CNTFET Based Operational Amplifier Circuit
Fig 2: Schematic of a basic two stage Op Amp.

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Comparison between two types of material used in
Transistors of Fig 1 and Fig 2
Table 1: Set of CNT’s Diameters Used for the Op Amp Design
where "a" is the carbon to carbon atomic
distance and it is
equal to 1.42 angstrom
Normal 7-99 angstrom transistor has a height of 0.65 cm and a diameter of 0.60 cm
It can be concluded that diameter of Transistor is greatly reduced
with usage of CNT material.

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