Pati S.K., Enoki T., Rao C.N. R. (eds.) Graphene and Its Fascinating Attributes

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Graphene and

Its Fascinating

Attributes

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World Scientic

Graphene and

Its Fascinating

Attributes

Editors

Swapan K. Pati

Jawarharlal Nehru Centre for Advanced Scientiﬁc Research, India

Toshiaki Enoki

Tokyo Institute of Technology, Japan

C. N. R. Rao

Jawarharlal Nehru Centre for Advanced Scientiﬁc Research, India

7989 tp.indd 2 3/4/11 11:45 AM

British Library Cataloguing-in-Publication Data

A catalogue record for this book is available from the British Library.

For photocopying of material in this volume, please pay a copying fee through the Copyright

Clearance Center, Inc., 222 Rosewood Drive, Danvers, MA 01923, USA. In this case permission to

photocopy is not required from the publisher.

ISBN-13 978-981-4329-35-4

ISBN-10 981-4329-35-5

electronic or mechanical, including photocopying, recording or any information storage and retrieval

system now known or to be invented, without written permission from the Publisher.

Published by

World Scientific Publishing Co. Pte. Ltd.

5 Toh Tuck Link, Singapore 596224

USA office: 27 Warren Street, Suite 401-402, Hackensack, NJ 07601

UK office: 57 Shelton Street, Covent Garden, London WC2H 9HE

Printed in Singapore.

GRAPHENE AND ITS FASCINATING ATTRIBUTES

Lakshmi - Graphene & Its Fascinating.pmd 2/1/2011, 1:51 PM1

Preface

Carbon is the fourth most abundant element on earth. The diversity in

bonding makes carbon the most important element in a variety of

disciplines. The catenation property, i.e. the ability to form large stable

frameworks of interconnecting bonds with different hybridization allows

carbon to form innumerable compounds with varying dimensionalities. A

recent addition to this large family of carbon allotropes is Graphene, a

two-dimensional monolayer of sp

carbon atoms arranged in a honeycomb

lattice. Graphene can be considered as the parental compound for the

carbon allotropes of other dimensionalities. The wrapping of graphene,

introducing curvature in terms of intervening five membered rings leads

to fullerene. Rolling of graphene segments with different boundaries

results in carbon nanotubes of varying chiralities. Three-dimensional

graphite can be obtained by the stacking of graphene layers, stabilized by

weak interlayer interactions. Graphene has also made it possible to

understand properties in low-dimension. It has opened huge possibilities

in electronic device fabrication and has also shown much promise in

replacing silicon-based electronics. A number of fascinating properties

including the observation of integer quantum Hall effect even at room

temperature, breakdown of adiabatic Born–Oppenheimer approximation,

realization of Klein paradox, possibilities of high T

superconductivity,

metal-free magnetism, ballistic electronic propagation, charge-carrier

doping, chemical activities and high surface area, have made graphene

the material of the 21

century. The diverse structural and electronic

features as well as exciting applications have attracted theoretical and

experimental scientists all over the world to explore this low dimensional

material.

In November 2009, we had a successful India–Japan bilateral meeting

on graphene at the JNCASR, Bangalore, India. The meeting covered all

vi Preface

the fast developing facets of graphene presented by leading experts in the

subject. We, therefore, considered it to be of value to present the

proceedings of the meeting in the form of a book to the scientific

community. While the subject is in a highly active phase of development,

we present in this volume the physics, chemistry and engineering of this

century material.

There are 15 chapters in the book. In the first chapter, Rao et al. have

presented a number of experimental routes to synthesize and characterize

one to few layers graphene. They have also presented functionalization

of graphene by employing both covalent and non-covalent modifications

and have studied in detail a number of properties including surface and

magnetic properties and doping of graphene by electron donor and

acceptor molecules. In the second chapter, Sampath et al. report the

synthesis and characterization of graphene-bimetallic alloy composites

which show good elctro-catalytic, electro-sensing and electrochemical

capacitors properties. Kubo et al. have analyzed theoretically the singlet

open-shell character of polyperiacenes based on Clar’s rule and quantum

chemical calculations in Chapter 3. They have also isolated a few

polyperiacenes experimentally.

The fourth chapter describes the work of Pati et al. on the effect of

charge transfer on the low-energy characteristics of graphene when it is

decorated with donor acceptor organic molecules and metal nanoparticles

using ab-initio methods. In the fifth chapter, Waghmare et al. have

studied the uni-axial strain in graphene and its BN analogue theoretically

and have explored the reason for the buckling of the two-dimensional

layer using ab-initio modeling.

R. Saito presents the Raman spectroscopy of graphene edge from the

theoretical point of view in Chapter 6. He shows that the LO and TO

phonon modes show an opposite polarization dependence in the

intensities because of the symmetry of the graphene nanoribbon edges. In

the seventh chapter, Sood et al. have discussed the Raman spectroscopy

of single and bilayer graphene as a function of Fermi level shift achieved

by electrochemical top gating. Combining the transport and in-situ

Raman studies of the field effect devices, they have shown a quantitative

understanding of the phonon renormalization due to the doping. T. Ando

has reviewed the long-wave length acoustic and optical phonon and

Preface vii

zone-boundary phonons in graphene and carbon-nanotubes and their

interaction with electron from a theoretical point of view in Chapter 8.

The author has discussed at length the resistivity and conductivity limits

and the frequency shift and broadening properties related to various

phonon modes in graphene and carbon nanotubes.

In the nineth chapter, Enoki et al. investigate edge states of graphene

using UHV-STM/STS techniques. They have shown the unconventional

magnetic properties of the edge state in the zigzag edges using activated

carbon fibers consisting of 3D network of nanographene sheets. In the

subsequent chapter, K. Wakabayashi discusses theoretically the transport

properties of graphene nanoribbons. He has shown that the graphene

nanoribons with zigzag edges subjected to long-ranged impurities could

provide a perfectly conducting channel.

Tsukagoshi et al. have reviewed the experiments on graphene

transistor for its potential use as an atomic film switching device in

Chapter 11. They have discussed the preparation and characterization of

layered graphene structures and their novel fabrication technique of gate

electrodes specialized for the graphene system which is useful for

passing of high electric field in the transistor geometry. In Chapter 12,

K. Sengupta has theoretically analyzed the Kondo effect in graphene

which can be tuned by gate voltage. He argues that graphene might

provide the first example of experimental realization of non-Fermi liquid

ground states via multichannel Kondo effect. Chapter 13

contains the

work of Ghosh et al. on experimental studies of low frequency

fluctuations in electrical resistance of graphene based field-effect devices

with varying layer thickness. They have carried out measurements on the

low frequency resistance noise in bilayer graphene flakes as a function of

charge density and inter-electrode electric field, and analyzed their

results with an analytical model.

In Chapter 14, Shiraishi et al. have studied the spin transport

properties of single and multilayer graphene experimentally. They have

described in detail the generation of pure spin current in graphene and

the non-local spin transport. The book finishes with an overview by

Baskaran, who has discussed at length various unanticipated and

emergent properties of graphene because of complexity, theoretically. In

particular, he has reviewed the possibility and realization of spin-1

viii Preface

collective mode, room temperature superconductivity, composite Fermi

sea, two-channel Kondo effect in graphene with doping and with external

fields.

We believe that the 15 chapters in the book bring out the flavor of the

subject nicely and show that research on graphene is emerging to be of

major interest. We earnestly hope that the book will be found beneficial

by students, teachers and practitioners.

S. K. Pati, T. Enoki and C. N. R. Rao

Contents

Preface v

Chapter 1 Graphene: Synthesis, Functionalization and Properties 1

C. N. R. Rao, K. S. Subrahmanyam,

H. S. S. Ramakrishna Matte and A. Govindaraj

1. Introduction 1

2. Synthesis 4

3. Functionalization and Solubilization 9

4. Surface Properties 12

5. Interaction with Electron Donor and Acceptor

Molecules 13

6. Decoration of Graphene with Metal Nanoparticles 18

7. Magnetic Properties 19

8. Inorganic Graphene Analogues 21

References 27

Chapter 2 Synthesis and Characterization of Exfoliated

Graphene- and Graphene Oxide-Based Composites 33

K. R. Rasmi, K. Chakrapani and S. Sampath

1. Introduction 33

2. Experimental Section 34

2.1. Materials 34

2.2. Synthesis of exfoliated graphene oxide 34

2.3. Synthesis of EGO- Au-Ag alloy composites 34

2.3. Synthesis of GO-Co

composite 35

2.4. Synthesis of EGO-RuOx composite 35

2.5. Materials characterization 36