Efficient Coupling of Optical Energy for Rapid Catalyzed Nanomaterial Growth: High-Quality Carbon Nanotube Synthesis at Low Substrate Temperatures

Ahmad, Muhammad; Anguita, José V.; Stolojan, Vlad; Carey, J. D.; Silva, S. Ravi P.

doi:10.1021/am400542u

Cited by 22 publications

(39 citation statements)

References 34 publications

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“…For excluding the influence of diameter, Figure 10 presents the results of the time averaged interconnection configurations between different pairs of SWNTs with similar diameter at a temperature of 800 K. There are not significant differences between configurations shown in Figures 8 and 10. At the same time, in the simulation, the evolution of atomic configuration between metallic SWNT (9,9) and semiconducting SWNT (10,8), is also performed under the same simulation diameters, which is shown in Figure 11. Though the atomic structures in left SWNT are loose in the simulation time of 100 ps, the tight atomic structures are accomplished in 200 ps and the final interconnection configuration is similar to that in Figures 8 and 10.…”

Section: Resultsmentioning

confidence: 99%

Nanoscale Soldering of Axially Positioned Single-Walled Carbon Nanotubes: A Molecular Dynamics Simulation Study

Cui

Yang

Zhou

et al. 2014

ACS Appl. Mater. Interfaces

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The miniaturization of electronics devices into the nanometer scale is indispensable for next-generation semi-conductor technology. Carbon nanotubes (CNTs) are considered to be the promising candidates for future interconnection wires. To study the carbon nanotubes interconnection during nanosoldering, the melting process of nanosolder and nanosoldering process between single-walled carbon nanotubes are simulated with molecular dynamics method. As the simulation results, the melting point of 2 nm silver solder is about 605 K because of high surface energy, which is below the melting temperature of Ag bulk material. In the nanosoldering process simulations, Ag atoms may be dragged into the nanotubes to form different connection configuration, which has no apparent relationship with chirality of SWNTs. The length of core filling nanowires structure has the relationship with the diameter, and it does not become longer with the increasing diameter of SWNT. Subsequently, the dominant mechanism of was analyzed. In addition, as the heating temperature and time, respectively, increases, more Ag atoms can enter the SWNTs with longer length of Ag nanowires. And because of the strong metal bonds, less Ag atoms can remain with the tight atomic structures in the gap between SWNT and SWNT. The preferred interconnection configurations can be achieved between SWNT and SWNT in this paper.

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Section: Resultsmentioning

confidence: 99%

Nanoscale Soldering of Axially Positioned Single-Walled Carbon Nanotubes: A Molecular Dynamics Simulation Study

Cui

Yang

Zhou

et al. 2014

ACS Appl. Mater. Interfaces

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“…Nanotube growth is carried out in a PTCVD system at substrate bulk temperature of 350–440 °C. The method for PTCVD growth of carbon nanomaterials has been reported elsewhere . Briefly, during PTCVD, energy is delivered directly to the catalyst from the top by optical lamps situated in the head of the reaction chamber, while the sample is placed on a water‐cooled platform, as shown in Figure b.…”

Section: Methodsmentioning

confidence: 99%

“…PTCVD is a potentially large scale production method that relies on high power optical sources to deliver energy onto the growth surface while the bulk of the substrate is held at much lower temperatures . We show that high quality growth of CNTs is achieved through engineering the thickness of the underlying TiN layer such that the energy necessary for growth is concentrated into the metallic catalyst with little being transmitted to the underlying substrate.…”

Section: Introductionmentioning

confidence: 99%

High Quality Carbon Nanotubes on Conductive Substrates Grown at Low Temperatures

Ahmad

Anguita

Stolojan

et al. 2015

Adv Funct Materials

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Keywords: nanomaterials, carbon nanotubes, photothermal chemical vapor deposition, low temperature growth 2 For carbon nanotubes (CNTs) to be exploited in electronic applications the growth of high quality material on conductive substrates at low temperatures (< 450 o C) is required. CNT quality is known to be strongly degraded when growth is conducted on metallic surface at low temperatures using conventional chemical vapor deposition (CVD). Here, we demonstrate production of high quality vertically-aligned CNTs at low substrate temperatures (350 -440 o C) on conductive TiN thin film using photo-thermal CVD by confining the heat required for growth to just the catalyst using an array of optical lamps and by optimizing the thickness of the TiN under-layer. The thickness of the TiN plays a crucial role in determining various properties including diameter, material quality, number of shells and metallicity. The highest structural quality with a visible Raman D-to G-band intensity ratio as low as 0.13 is achieved for 100 nm TiN thickness grown at 420 o C; a record low value for low temperature CVD grown CNTs. Electrical measurements of high density CNT arrays show the resistivity to be 1.25×10 -2 Ωcm represents some of the lowest values reported. Finally, the broader aspects of using this approach as a scalable technology for carbon nanomaterial production are also discussed.3

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“…Finally, CNTs were grown on the electrode areas using photo‐thermal chemical vapour deposition (PT‐CVD), a process documented elsewhere . The samples were annealed at 2 Torr, using a lamp power output of 42.5 %, under a flow rate of 100 sccm hydrogen, for 10 minutes.…”

Section: Methodsmentioning

confidence: 99%

Highly Sensitive Dopamine Detection Using a Bespoke Functionalised Carbon Nanotube Microelectrode Array

et al. 2017

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Understanding how the brain works requires developing advanced tools that allow measurement of bioelectrical and biochemical signals, including how they propagate between neurons. The introduction of nanomaterials as electrode materials has improved the impedance and sensitivity of microelectrode arrays (MEAs), allowing high quality recordings of single cells in situ using electrode diameters of ≤20 μm. MEAs also have the potential to measure electroactive biological molecules in situ, such as dopamine, a neurotransmitter in the nervous system. Thus, this work focused on fabricating a functionalised carbon nanotube (CNT)‐based MEA to demonstrate its potential for future measurement of small signals generated from excitable cells. To this end, the functionalised CNT MEA has recorded one of the lowest electrochemical interfacial impedances available in the literature, 2.8±0.2 kΩ, for an electrode of its geometric surface area. Electrochemical detection of dopamine revealed again one of the best sensitivity values per area available in the literature, 9.48 μA μM−1 mm−2. Additionally, a limit of detection of 7 nM was recorded for dopamine using the functionalised CNT MEA, with selectivity against common electrochemical interferents such as ascorbic acid. These results indicate improvement beyond currently available MEAs, along with the feasibility of using these devices for multi‐site detection of physiologically relevant electroactive biomolecules.

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Efficient Coupling of Optical Energy for Rapid Catalyzed Nanomaterial Growth: High-Quality Carbon Nanotube Synthesis at Low Substrate Temperatures

Abstract: The synthesis of high quality nanomaterials depends on the efficiency of the catalyst and the growth temperature. In order to produce high quality material high growth temperatures

Cited by 22 publications

References 34 publications

Nanoscale Soldering of Axially Positioned Single-Walled Carbon Nanotubes: A Molecular Dynamics Simulation Study

Nanoscale Soldering of Axially Positioned Single-Walled Carbon Nanotubes: A Molecular Dynamics Simulation Study

High Quality Carbon Nanotubes on Conductive Substrates Grown at Low Temperatures

Highly Sensitive Dopamine Detection Using a Bespoke Functionalised Carbon Nanotube Microelectrode Array

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