Title

Structural Evolution of Reduced Graphene Oxide of Varying Carbon sp(2) Fractions Investigated via Coulomb Blockade Transport

Authors

Authors

D. Joung;S. I. Khondaker

Comments

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Abbreviated Journal Title

J. Phys. Chem. C

Keywords

ARRAYS; NANOPARTICLES; FILMS; DOTS; Chemistry, Physical; Nanoscience & Nanotechnology; Materials Science, ; Multidisciplinary

Abstract

We investigate the structural evolution of reduced graphene oxide (RGO) sheets with carbon sp(2) fractions varying from 55 to 80% using low-temperature Coulomb blockade (CB) transport. At 4.2 K, all RGO sheets exhibit a complete suppression of current (CB) below a threshold voltage V-v the value of which decreased from 3.34 to 0.25 V with increasing carbon sp(2) fraction. From the temperature-dependent V-v we calculate an effective charging energy and individual graphene domain size of 160 meV and 1.34 nm at 55% carbon sp(2) fractions, respectively. These values are 20 meV and 4.18 nm at 80% carbon sp(2) fractions, respectively. This implies that with increasing reduction, newly formed sp(2) domains increase the effective size of the graphene domain. For an applied voltage V > V-v the current I follows a scaling law I similar to [(V - V-t)/V-t](alpha) where the scaling parameter alpha increases from 2.11 to 3.40 with increasing sp(2) fraction, suggesting that increasing sp(2) fraction creates more topological defects on the RGO. Our report provides a much desired insight into the structural evolution of RGO sheets.

Journal Title

Journal of Physical Chemistry C

Volume

117

Issue/Number

50

Publication Date

1-1-2013

Document Type

Article

Language

English

First Page

26776

Last Page

26782

WOS Identifier

WOS:000328920500043

ISSN

1932-7447

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