In situ Raman studies of single-walled carbon nanotubes grown by local catalyst heating

Dittmer, Staffan; Olofsson, Niklas; Weis, Johan Ek; Nerushev, Oleg; Gromov, Andrey; Campbell, Eleanor E. B.

doi:10.1016/j.cplett.2008.04.008

Cited by 17 publications

(32 citation statements)

References 14 publications

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“…Dittmer et al used ethylene as a precursor and took D, G and RBM snapshots in situ, although this was after cooling to room temperature for various growth durations [3]. The RBM density was found to increase, and a subtle shift of RBM to large diameter nanotubes was suggested.…”

Section: Resultsmentioning

confidence: 99%

“…This was for thin À lm À metal catalysts on silicon dioxide and using ethanol vapor as the carbon source. More recently in situ Raman spectroscopy of radial breathing mode (RBM), D and G bands, has been reported for an iron thin Àlm catalyst on alumina, using ethylene as the carbon À source, with a micro-heating approach [3]. In that case, however, spectra were taken only after cooling to room temperature.…”

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confidence: 99%

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The dynamics of the nucleation, growth and termination of single-walled carbon nanotubes from in situ Raman spectroscopy during chemical vapor deposition

2009

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The dynamics of the chemical vapor deposition (CVD) of single-walled carbon nanotubes (SWNTs) is extracted experimentally using in situ Raman spectroscopy. Nanotubes are grown using a thin À lm cobalt catalyst and À an ethanol precursor in a miniature hot walled reactor with optical access. Raman spectra at room temperature and at the growth temperature are compared for two growth temperatures. The evolution of the G-band, D-band, and radial breathing mode (RBM) is tracked at the growth temperature with time resolution of a few seconds. There are three identifiable phases in the evolution of the Raman signal intensity: an initial exponential increasing phase, a linear growth phase, and a saturation phase. In situ optical spectroscopy thus enables the study of nucleation, steady growth, and deactivation processes to be investigated separately in real time. The evolution curves for all bands (G, D, and RBM), when scaled, collapse onto the same curve, to within experimental uncertainty.

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Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

The dynamics of the nucleation, growth and termination of single-walled carbon nanotubes from in situ Raman spectroscopy during chemical vapor deposition

2009

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“…13 This allows in situ temperature measurement with high spatial resolution. An advantage of this method is that the emission depends on the actual temperature of the heater surface/catalyst which eliminates errors related to heat losses and contact thermal resistance common for contact probe methods such as thermocouples and thermal resistors.…”

Section: Methodsmentioning

confidence: 99%

Growth of Aligned MWNT Arrays Using a Micrometer Scale Local-Heater at Low Ambient Temperature

Dittmer¹,

Ek-Weis²,

Nerushev³

et al. 2010

J. Nanosci. Nanotech.

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Ambient room temperature growth of aligned multi-walled carbon nanotube arrays on micrometer scale local heaters is demonstrated. High growth rates of up to 8.8 microm per second have been achieved and the growth has been monitored in situ using optical microscopy. The growth starts and ends abruptly over the length of the local heater. The terminal length of the nanotubes shows a clear dependence on growth temperature and small inhomogeneities in temperature across the heater are seen to lead to interesting microstructure of the arrays. The activation energy for growth was seen to be consistent with earlier reports for acetylene growth of nanotubes on iron catalysts.

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“…To better understand growth, nucleation, and termination processes, a considerable effort has been made to investigate the dynamics of nanotube CVD growth in situ. Because Raman spectroscopy is a highly developed characterization tool for nanocarbons that can be adapted for in situ use during nanotube CVD, [1][2][3][4][5][6][7] it is a good approach for obtaining dynamical growth data.…”

Section: Introductionmentioning

confidence: 99%

Phases of Carbon Nanotube Growth and Population Evolution from in Situ Raman Spectroscopy during Chemical Vapor Deposition

2010

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The dynamical evolution of nanotube chemical vapor deposition growth was investigated by in situ spectroscopy of three main Raman bands: G, D, and RBM. The evolution in diameter distribution is inferred from RBM and G bands, and the evolution in crystallinity is determined from D and G bands. A consistent sequence of the growth evolution is observed, with four discernible phases: incubation, acceleration, linear growth, and termination. The temperature dependence of each of these stages of growth is experimentally determined, and characteristic energy scales apparently associated with each phase are extracted. The growth becomes slower as the temperature increases, with activated, parasitic reactions suggested as a cause. We explore to what extent one diameter grows in comparison to another and thus gain some insight into how the nanotube population changes with time.

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In situ Raman studies of single-walled carbon nanotubes grown by local catalyst heating

Cited by 17 publications

References 14 publications

The dynamics of the nucleation, growth and termination of single-walled carbon nanotubes from in situ Raman spectroscopy during chemical vapor deposition

The dynamics of the nucleation, growth and termination of single-walled carbon nanotubes from in situ Raman spectroscopy during chemical vapor deposition

Growth of Aligned MWNT Arrays Using a Micrometer Scale Local-Heater at Low Ambient Temperature

Phases of Carbon Nanotube Growth and Population Evolution from in Situ Raman Spectroscopy during Chemical Vapor Deposition

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