Presentation topic: Graphene Nanoribbons

Presented to: Rethwan Faiz Course name: Power System Analysis Section: [G]

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Presentation members

Presented by:

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SL Name I.D1 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

Outlines

GrapheneCarbon nanotubes (CNT)Graphene nanoribbons (GNR)Comparison between CNT and GNRSynthesis methods of GNRsApplications of GNRsOp amp circuit using CNTFET

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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

Properties of Graphene

pure substance, orderly structure based on tight, regular, atomic bondingGraphene is believed to be the strongest material yet discoveredHas high thermal conductivityCan conduct electricity very wellIs very light and transparentSheets 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

Graphene Nanoribbons (GNR)

also called nano-graphite ribbonscarbon based materialone-dimensional structures with hexagonal two dimensional carbon latticesa derivative of GrapheneGraphene ribbons were introduced as a theoretical model by Mitsutaka Fujita

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types of GNR edges

Properties of GNR

GNR inherits almost all the attractive properties of the carbon nanotube and graphene.Has additional benefit of a tunable band gapZigzag & 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

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 moleculesunzipping of carbon nanotubes (CNTs)

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Applications of GNRs

Light emitting diodesP-N junctionsSchottky diodesField effect transistorsConductive electrodesSolar cell systemsField 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 inTransistors 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 isequal 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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