Grazing incidence X-ray diffraction study on carbon nanowalls

We synthesized carbon nanowalls on a Si substrate by microwave surface -wave plasma chemical vapor deposition. The Raman scattering ID/IG ratio was changed by altering the DC bias applied to the growth substrate and the decrease in ID/IG with increasing DC bias appears to arise from the growing length of the carbon nanowalls. The ultrasonically separated carbon nanowalls in ethanol exhibited strong 2D -peak intensity and significant graphitization. A graphite layer of approximately 10 nm grew parallel to the substrate initially, and the carbon nanowalls grew on top of that. When the nanowalls were dispersed in ethanol and spin-coated onto PET, they exhibited a transmittance of 81% and a sheet resistance of 52 kΩ/□ without reduction treatment used in the graphene oxide.

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“…The growth process of carbon nanowalls has been reported by several groups [21][22][23]. We compare those reports with the results of this study.…”

Section: Tem Observationsupporting

confidence: 75%

DC Biasing Effects on Properties of Carbon Nanowalls by Microwave Surface-Wave Plasma Chemical Vapor Deposition and Towards Transparent Electrode

Ichimura

Hayashi

2016

Trans. Mat. Res. Soc. Japan

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“…109 Zhang et al, attributed the formation of nucleation sites to the protruding particles formed at the substrate surface which were considered to cause accumulation of hydrocarbon ions. 58 It was accepted by some groups that the graphene growth orientation underwent a change from initially parallel to perpendicular to the substrate, caused by the formation of new crystalline phases 149 or the socalled Volmer-Weber mechanism. 79,96 Yoshimura et al conducted grazing incidence X-ray diffraction study on the asgrown deposits and suggested that it was the formation of a new crystalline phase (possibly a carbon allotrope) at the critical deposition time that changed the orientation of the graphene layers.…”

Section: Challengementioning

confidence: 99%

Plasma-enhanced chemical vapor deposition synthesis of vertically oriented graphene nanosheets

et al. 2013

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Vertically oriented graphene (VG) nanosheets have attracted growing interest for a wide range of applications, from energy storage, catalysis and field emission to gas sensing, due to their unique orientation, exposed sharp edges, non-stacking morphology, and huge surface-to-volume ratio. Plasma-enhanced chemical vapor deposition (PECVD) has emerged as a key method for VG synthesis; however, controllable growth of VG with desirable characteristics for specific applications remains a challenge. This paper attempts to summarize the state-of-the-art research on PECVD growth of VG nanosheets to provide guidelines on the design of plasma sources and operation parameters, and to offer a perspective on outstanding challenges that need to be overcome to enable commercial applications of VG. The review starts with an overview of various types of existing PECVD processes for VG growth, and then moves on to research on the influences of feedstock gas, temperature, and pressure on VG growth, substrate pretreatment, the growth of VG patterns on planar substrates, and VG growth on cylindrical and carbon nanotube (CNT) substrates. The review ends with a discussion on challenges and future directions for PECVD growth of VG.

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“…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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Grazing incidence X-ray diffraction study on carbon nanowalls

Cited by 32 publications

References 18 publications

DC Biasing Effects on Properties of Carbon Nanowalls by Microwave Surface-Wave Plasma Chemical Vapor Deposition and Towards Transparent Electrode

DC Biasing Effects on Properties of Carbon Nanowalls by Microwave Surface-Wave Plasma Chemical Vapor Deposition and Towards Transparent Electrode

Plasma-enhanced chemical vapor deposition synthesis of vertically oriented graphene nanosheets

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

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