In the present letter, field emission property of highly wrinkled hydrogen exfoliated graphene (HEG) was studied using an indigenously fabricated setup under ∼ 10-6 mbar pressure. Graphene was coated on a flexible carbon cloth by spin coating for the field emission study. The turn on voltage obtained for a HEG field emitter is around 1.18 V/μm. Further, the field emission property of HEG was improved by decorating metal oxide over HEG. The stability of the field emitter was tested and field enhancement factor was calculated using Fowler-Nordheim plot. © 2011 American Institute of Physics.

Sundara Ramaprabhu

Department Of Physics

CARBON CLOTHS

COLD FIELD EMISSIONS

FIELD EMISSION PROPERTY

FIELD EMITTER

Field enhancement factor

FOWLER-NORDHEIM PLOTS

Metal oxides

field emission

Field emission cathodes

Hydrogen

Metallic compounds

Graphene

Fulltext

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Cold field emission from hydrogen exfoliated graphene composites

Applied Physics Letters

Graphene sheets that are now routinely obtained by the exfoliation/ reduction of graphite oxide exhibit Raman spectra unlike traditional graphene systems. The general attributes of the Raman spectra of these 'wrinkled graphene' are first reaffirmed by evaluating the spectra of samples prepared by seven different exfoliation-reduction methods. These graphene sheets exhibit highly broadened D and G Raman bands and in addition, have a modulated bump in place of the conventional 2D (G′) band. It is shown that the high wavenumber 'bump' can be resolved into the conventional 2D band and several defect activated peaks such as G*, D+D′ and 2D′. The broad G band could also be deconvoluted into the actual G band and the D′ and, thereby attributing the broadening in the G band to the presence of this defect activated band. Two additional modes, named as D*at 1190 cm-1 and D**at ∼1500 cm-1 could be identified. These peculiar features in the Raman spectrum of 'graphene' are attributed to the highly disordered and wrinkled (defective) morphology of the sheets. The affect of defects are further augmented due to the finite crystallite size of these graphene sheets. The dispersion in the band positions and peak intensities with respect to the laser energy are also demonstrated. Copyright 2012 Author(s).

AIP Advances

A Raman spectroscopic investigation of graphite oxide derived graphene

The present work describes the synthesis of cobalt oxide nanoparticle decorated hydrogen exfoliated graphene (Co 3O 4/HEG) by exfoliating graphite oxide in hydrogen atmosphere followed by chemical reduction of cobalt salt using sodium borohydride. The synthesized material has been characterized by X-ray diffractometry, thermogravimetric analysis, field emission scanning electron microscopy and transmission electron microscopy. A flexible field emitter has been fabricated by spin coating this material on carbon cloth. Electron emission characteristics of Co 3O 4/HEG have been investigated using an in-house fabricated setup and analyzed using Fowler-Nordheim equation. Turn-on and threshold fields of 1.12 and 1.35 V μm -1, respectively have been observed for this material. Moreover, the present field emitter shows a reasonably good stability and repeatability. © 2012 Elsevier B.V. All rights reserved.

Materials Chemistry and Physics

A facile synthesis and field emission property investigation of Co 3O 4 nanoparticles decorated graphene

The electron field emission from metal nanoparticle decorated hydrogen exfoliated graphene (metal/HEG) occurs at low turn on and threshold fields due to its low work function and high field enhancement factor. © 2011 The Royal Society of Chemistry.

Nanoscale

Effect of metal nanoparticles decoration on electron field emission property of graphene sheets

Multi-walled carbon nanotubes (MWNT) have been synthesized by chemical vapour decomposition (CVD) of acetylene over Rare Earth (RE) based AB 2 (DyNi 2) alloy hydride catalyst. The as-grown carbon nanotubes were purified by acid and heat treatments and characterized using powder X-ray diffraction, Scanning Electron Microscopy, Transmission Electron Microscopy, Thermo Gravimetric Analysis and Raman Spectroscopy. Fully carbon based field emitters have been fabricated by spin coating a solutions of both as-grown and purified MWNT and dichloro ethane (DCE) over carbon paper with and without graphitized layer. The use of graphitized carbon paper as substrate opens several new possibilities for carbon nanotube (CNT) field emitters, as the presence of the graphitic layer provides strong adhesion between the nanotubes and carbon paper and reduces contact resistance. The field emission characteristics have been studied using an indigenously fabricated set up and the results are discussed. CNT field emitter prepared by spin coating of the purified MWNT-DCE solution over graphitized carbon paper shows excellent emission properties with a fairly stable emission current over a period of 4 h. Analysis of the field emission characteristics based on the Fowler-Nordheim (FN) theory reveals current saturation effects at high applied fields for all the samples.

Nanoscale Research Letters

Effect of purity and substrate on field emission properties of multi-walled carbon nanotubes

The Journal of Physical Chemistry C

First-Principles Study of Field Emission Properties of Graphene-ZnO Nanocomposite

Journal of Materials Chemistry

Graphene synthesis via hydrogen induced low temperature exfoliation of graphite oxide

A Study on Field Emission Characteristics of Planar Graphene Layers Obtained from a Highly Oriented Pyrolyzed Graphite Block

Small

Carbon-Nanotube-Polymer Nanocomposites for Field-Emission Cathodes

Journal	Applied Physics Letters
ISSN	00036951
Open Access	No