Rapid synthesis of few-layer graphene over Cu foil

Kumar, Anurag; Voevodin, Andrey A.; Zemlyanov, Dmitry; Zakharov, Dmitri N.; Fisher, Timothy S.

doi:10.1016/j.carbon.2011.11.033

Cited by 74 publications

(47 citation statements)

References 38 publications

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“…The morphology of the purified product was investigated by SEM and TEM/HRTEM. Figure 2 shows representative SEM images of graphene at low (a) and high (b) magnification, which are in excellent agreement with earlier reports 30. The edges of the bent graphitic sheets are clearly visible in Figure 2 a, while the white spots (marked with arrows in Figure 2 b) represent metallic nanoparticles decorating the graphene sheets during the synthesis process (subsequently referred to as Gr–Au–Ag).…”

Section: Resultssupporting

confidence: 87%

Real‐Time Probing of Ion Pairing Dynamics with 2DIR Spectroscopy

Park

Choi

et al. 2010

ChemPhysChem

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Chemical exchange two-dimensional infrared (2DIR) spectroscopy is applied to investigate ion pairing dynamics occurring on picosecond timescales. SeCN(-) ion is used as a vibrational probe. The SeCN(-) ion dissolved in N,N-dimethyl formamide (DMF) has a sufficiently long vibrational lifetime and can form a contact ion pair with Li(+) ion in DMF. The CN stretch frequency of the contact ion pair is significantly blue-shifted from that of free SeCN(-) so the free SeCN(-) ion can be spectrally distinct from the contact ion pair in DMF. Therefore, we were able to directly monitor the ion pairing dynamics of Li(+) and SeCN(-) in real time by using ultrafast 2DIR spectroscopy. As a result, we have determined the dissociation time constant of the LiSeCN contact ion pair to be 420±40 ps.

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Section: Resultssupporting

confidence: 87%

Real‐Time Probing of Ion Pairing Dynamics with 2DIR Spectroscopy

Park

Choi

et al. 2010

ChemPhysChem

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“…[10][11][12] Further, the observed results in terms of morphology and structural properties of NGSs grown by various groups are only in partial agreement, and sometimes even contradictory. 3, The reason for such variation and discrepancy among the published results could be due to different synthesis techniques and conditions, which make it difficult to give a unique interpretation for the growth and its properties.…”

Section: Introductionmentioning

confidence: 86%

“…Since then, several groups have explored the growth of VGNs on catalytic as well as non-catalytic metal / dielectric surfaces using various plasma based techniques such as microwave PECVD, dc plasma discharge, ICP-plasma and thermal plasma jet systems. [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] In an excellent review, Bo et al 11 summarized the influence of various key process parameters on the synthesis and growth model for NGSs on various types of substrates. In spite of several existing reports, herein we note that, still there is no unique theory that could unveil the atomistic growth mechanism and give a prescription to optimize the process parameters for a given plasma source.…”

Section: Introductionmentioning

confidence: 99%

Flipping growth orientation of nanographitic structures by plasma enhanced chemical vapor deposition

et al. 2015

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Nanographitic structures (NGSs) with multitude of morphological features are grown on SiO2/Si substrates by electron cyclotron resonance -plasma enhanced chemical vapor deposition (ECR-PECVD). CH4 is used as source gas with Ar and H2 as dilutants. Field emission scanning electron microscopy, high resolution transmission electron microscopy (HRTEM) and Raman spectroscopy are used to study the structural and morphological features of the grown films. Herein, we demonstrate, how the morphology can be tuned from planar to vertical structure using single control parameter namely, dilution of CH4 with Ar and/or H2. Our results show that the competitive growth and etching processes dictate the morphology of the NGSs. While Ar-rich composition favors vertically oriented graphene nanosheets, H2-rich composition aids growth of planar films.Raman analysis reveals dilution of CH4 with either Ar or H2 or in combination helps to improve the structural quality of the films. Line shape analysis of Raman 2D band shows nearly symmetric Lorentzian profile which confirms the turbostratic nature of the grown NGSs. Further, this aspect is elucidated by HRTEM studies by observing elliptical diffraction pattern. Based on these experiments, a comprehensive understanding is obtained on the growth and structural properties of NGSs grown over a wide range of feedstock compositions.This manuscript got published in RSC Adv., 2015,5, 91922-91931 web link : pubs.rsc.org/en/content/articlelanding/2015/ra/c5ra20820c

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“…Growth of petals does not require any supplemental heating. The growth substrate couples strongly with the plasma and which is sufficient to locally heat the substrate up to about 1000 1C [24,25,19,26]. Fig.…”

Section: Comparison With Experimentsmentioning

confidence: 99%