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Please use this identifier to cite or link to this item: http://dspace.library.iitb.ac.in/jspui/handle/100/16427

Title: Near room temperature reduction of graphene oxide Langmuir-Blodgett monolayers by hydrogen plasma
Authors: SINGH, G
BOTCHA, VD
SUTAR, DS
NARAYANAM, PK
TALWAR, SS
SRINIVASA, RS
MAJOR, SS
Issue Date: 2014
Publisher: ROYAL SOC CHEMISTRY
Citation: PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 16(23)11708-11718
Abstract: Langmuir-Blodgett monolayer sheets of graphene oxide (GO) were transferred onto Si and SiO2/Si, and subjected to hydrogen plasma treatment near room temperature. GO monolayers were morphologically stable at low power (15 W) plasma treatment, for durations up to 2 min and temperatures up to 120 degrees C. GO monolayers reduced under optimized plasma treatment conditions (30 s duration at 50 degrees C) exhibit a sheet thickness of (0.5-0.6) nm, high sp(2)-C content (75%), a low O/C ratio (0.16) and a significant red-shift of Raman G-mode to 1588 cm(-1), indicating efficient de-oxygenation and a substantial decrease of defects. A study of the valence band electronic structure of hydrogen plasma reduced GO monolayers shows an increase of DOS in the vicinity of the Fermi level, due to the increase of C 2p-pi states, and a substantial decrease of work function. These results, along with conductivity measurements and transfer characteristics, reveal the p-type nature of hydrogen plasma reduced GO monolayers, displaying a conductivity of (0.2-31) S cm(-1) and a field effect mobility of (0.1-6) cm(2) V-1 s(-1). Plasma treatment at higher temperatures results in a substantial increase in sp(3)-C/damaged alternant hydrocarbon content and incorporation of defects related to the hydrogenation of the graphitic network, as evidenced by multiple Raman features, including a large red-shift of D-mode to 1331 cm(-1) and a high I(D)/I(G) ratio, and supported by the appearance of mid-gap states in the vicinity of the Fermi level.
URI: http://dx.doi.org/10.1039/c4cp00875h
http://dspace.library.iitb.ac.in/jspui/handle/100/16427
ISSN: 1463-9076
1463-9084
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