Deposition of Graphene-like carbon on copper foil using Methane
Graphene, a two-dimensional carbon allotrope that is made up of single-layer sp2 hybridized carbon atoms arranged in a hexagonal configuration. Since graphene was discovered in year 2004, graphene research has surged exponentially owing to its unique and remarkable properties. A variety of method...
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| Format: | Thesis |
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| Language: | English |
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| Online Access: | http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/76623/1/Page%201-24.pdf http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/76623/2/Full%20text.pdf http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/76623/3/Declaration%20Form.pdf |
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| Summary: | Graphene, a two-dimensional carbon allotrope that is made up of single-layer sp2
hybridized carbon atoms arranged in a hexagonal configuration. Since graphene was
discovered in year 2004, graphene research has surged exponentially owing to its unique
and remarkable properties. A variety of methods have been proposed to synthesize
graphene layer of which the most promising method is using chemical vapour deposition
(CVD). However, there still lie a lot of issues about effects of reaction parameters and
growth mechanism in the catalytic growth using CVD method. For example, is the
separation of the graphene from the substrate and uniformity of graphene layer on the
substrate. In this study, catalytic decomposition of methane was employed for producing
graphene layer on copper foil. The reaction parameters in CVD process including reaction
times, reaction temperatures and methane flow rates were varied to study the impact of
these parameters on the graphene samples. Various characterization tests including
Scanning Electron Microscopy (SEM), Energy Dispersive X-ray (EDX), X-ray
diffraction (XRD), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS)
were carried out on the graphene samples produced. The agglomerations of carbon were
observed at the grain boundaries of the copper substrate. The carbon content on the
graphene sample increased when the reaction time, reaction temperature or methane flow
rate were increased. This indicated that more and more carbon atoms were deposited on
the copper foil when the reaction time, reaction temperature and methane flow rate were
increased. On the other hand, the weight percentage of carbon agglomeration at the grain
boundaries was higher than that of the centre of grains in all samples. Besides, XRD
diffraction peak for the copper oxide and small graphite peak at 2θ=26.5° were seen which
signified very low quantity of graphene-like carbon structures were formed under high
reaction times (90 and 300 seconds), high reaction temperature (1050°C) and methane
flow rates (200-600mlpm). In addition, XPS results confirmed the presence of the C1s
spectrum at 284.8eV which ascribed to the existence of sp2-hybridized carbon on the
samples. With this sp2-hybridized carbon, it is confirmed again very low amount of
graphene-like carbon materials were synthesized and distributed randomly on the surface
of our samples. However, no Raman peak at D(1350cm-1), G(1580cm-1) and 2D(2700cm-
1) were shown to represent the graphene on the sample but only the Raman peaks of
copper oxide were detected. From above results, the produced samples contain very small
amount of graphene layer due to two limitations: no hydrogen gas and high methane flow
rate were used. Furthermore, the presence of oxygen species in the CVD furnace even
further hinders the formation of graphene layer and eventually, the graphene layer was
less likely to be formed on the copper substrate. |
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