Distinct termination morphologies for vertically aligned carbon nanotube forests

Vinten, Phillip; Marshall, Paul; Jacques, Laurent; Finnie, Paul

doi:10.1088/0957-4484/21/3/035603

Cited by 27 publications

(48 citation statements)

References 40 publications

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“…Details can be found in a previous report. 15 Optical images were acquired through a long focal length microscope with a digital camera, with the color balance adjusted so the image on the monitor appeared as it does to the naked eye. A 1 mW HeNe ͑632.8 nm͒ laser, focused with a lens and passed through a variable intensity filter was used for laser illumination.…”

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confidence: 99%

“…The observed ripple spacing is similar to the average length over which nanotubes come into contact with one another in a forest. 15,16 The angular positions of the intensity maxima of a grating are given by the grating equation: n = d͑sin n + sin i ͒ where n is the order of the maximum ͑here n =1͒, is the wavelength observed at the maximum, d is the grating spaca͒ Electronic mail: paul.finnie@nrc-cnrc.gc.ca. ing, n is the angle of the maximum ͑angle of observation͒, and i is the angle of incidence.…”

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confidence: 99%

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Visible iridescence from self-assembled periodic rippling in vertically aligned carbon nanotube forests

Vinten

Jacques

Finnie

2010

Applied Physics Letters

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We observe iridescence in the form of spectrally dispersed white light reflected from the structured sidewalls of vertically aligned carbon nanotube forests. The iridescence is a result of diffraction from a self-assembled periodic rippling pattern on the forest sidewalls that acts as a reflection grating. We measure the grating spacing via white light and laser diffraction experiments and see good agreement with the spacing of the rippling pattern as measured via scanning electron microscopy. The periodic rippling pattern self-assembles during chemical vapor deposition growth of the forests.

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confidence: 99%

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confidence: 99%

Visible iridescence from self-assembled periodic rippling in vertically aligned carbon nanotube forests

Vinten

Jacques

Finnie

2010

Applied Physics Letters

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“…For example, the evolution of forest morphology was heavily studied using ex situ SEM, to reveal the mechanism of growth temination. 64,65 A large number of in situ and ex situ techniques were previously explored for the nondestructive characterization of CNT growth kinetics. For example, optical photography and videography, 67,68 optical interference, 69 single-slit laser diffractography, 70 time-resolved reflectivity, 9 laser triangulation, 71,72 and cycling of growth to create stacked structures visible by SEM.…”

Section: Cnt Growth and Terminationmentioning

confidence: 99%

Data-driven understanding of collective carbon nanotube growth by in situ characterization and nanoscale metrology

Bedewy

2016

J. Mater. Res.

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Aligned carbon nanotubes (CNTs) possess great potential for transforming the fabrication of advanced interfacial materials for energy and mass transport as well as for structural composites. Realizing this potential, however, requires building a deeper understanding and exercising greater control on the atomic scale physicochemical processes underlying the bottom-up synthesis and self-organization of CNTs. Hence, in situ nanoscale metrology and characterization techniques were developed for interrogating CNTs as they grow, interact, and self-assemble. This article presents an overview of recent research on characterization of CNT growth by chemical vapor deposition (CVD), organized into three categories based on the growth stage, for which each technique provides information: (I) catalyst preparation and treatment, (II) catalytic activation and CNT nucleation, and (III) CNT growth and termination. Combining all three categories together provides insights into building the process-structure relationship, and paves the way for producing tailored CNT structures having desired properties for target applications.

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“…The growth was tracked in situ with a camera and long working distance microscope optics directed at the growth sample at a glancing angle of ~5° to the plane of the sample (see figure 1). See our previous reports for a more detailed account (15). …”

Section: Ecs Transactions 35 (25) 3-12 (2011)mentioning

confidence: 99%

“…Gradual termination appears to have a plausible explanation in catalyst poisoning. There has been recent progress in understanding sudden termination, and several models have been proposed (15,17,18). One picture is that sudden termination comes simply from the cumulative effect of gradual termination, and the forest terminates once it falls below a threshold to be self-supporting (17).…”

Section: Introductionmentioning

confidence: 99%

Morphological Instabilities and the Dynamics of Carbon Nanotube Forest Growth

et al. 2011

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Vertically aligned carbon nanotube forests show various morphologies on both macro-and micro-scales. These morphologies are a result of growth mechanisms and interactions between nanotubes. By investigating these morphologies, we study both the growth mechanisms and the interactions. We examine forest morphologies in situ, dynamically during chemical vapor deposition growth and ex situ, post growth. In situ observations allow the separate characterization of nucleation, growth and termination phases, and the exploration of connections between morphology and growth. Forests systematically show different morphologies, ranging from uniform to cracked, delaminated, and periodically rippled. These are discussed in terms of the balance of forces within the forests including cohesion, adhesion, and stiffness. We propose a simplified model that predicts termination as a result of an imbalance in the forces present. We show that growth rate differences drive many morphological effects, and these differences originate in the nucleation phase due to gas diffusion.

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Distinct termination morphologies for vertically aligned carbon nanotube forests

Cited by 27 publications

References 40 publications

Visible iridescence from self-assembled periodic rippling in vertically aligned carbon nanotube forests

Visible iridescence from self-assembled periodic rippling in vertically aligned carbon nanotube forests

Data-driven understanding of collective carbon nanotube growth by in situ characterization and nanoscale metrology

Morphological Instabilities and the Dynamics of Carbon Nanotube Forest Growth

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