Ref HAL: hal-00514937_v1
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We have developed a versatile catalyst-assisted chemical vapor deposition (CVD) technique for the synthesis of single-walled carbon nanotubes (SWNTs) from discrete nickel nanoparticles (average diameter of 4.7 ± 1.5 nm). Atomic force microscopy (AFM), transmission electron microscopy (TEM) and electron diffraction are used to characterize these as-grown nanotubes. On a particular sample we found that the SWNTs have an average chiral angle of 25.3°. This result shows that a control of the chiral angle of SWNT with large diameters (mean diameter = 1.75 nm) and with a relatively broad diameter distribution (standard deviation = 0.5 nm) is achievable to a certain extent.

Ref HAL: hal-00498747_v1
PMID 16706422
DOI: 10.1021/jp061181f
WoS: 000237626400006
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11 Citations
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We demonstrate the use of sequential catalytic growth to encapsulate iron, nickel-iron, and iron-cobalt phosphide catalyst nanoparticles periodically along the entire lengths of carbon nanotubes. Investigations by local electron spectroscopies and electron diffraction reveal the compositions and crystal structures of the encapsulated particles. Significantly, high spatial resolution magnetic characterization using magnetic force microscopy and off-axis electron holography demonstrates that encapsulated iron-cobalt phosphide nanoparticles are ferromagnetic at room temperature, in accordance with the properties of bulk metal phosphides of the same structure and composition.

Commentaires: ISI Document Delivery No.: 043UB Times Cited: 0 Cited Reference Count: 22 Cited References: AJAYAN PM, 1993, NATURE, V361, P333 AJAYAN PM, 1993, NATURE, V362, P522 BODE M, 1998, PHYS REV LETT, V81, P4256 DUJARDIN E, 1994, SCIENCE, V265, P1850 DUNINBORKOWSKI RE, 2004, ENCY NANOSCIENCE NAN, V3, P41 DUNINBORKOWSKI RE, 2004, MICROSC RES TECHNIQ, V64, P390 ELIAS AL, 2005, NANO LETT, V5, P467 FRUCHART R, 1969, J APPL PHYS, V40, P1250 GOTO M, 1977, JPN J APPL PHYS, V16, P2175 HSU WK, 1995, NATURE, V377, P687 IIJIMA S, 1991, NATURE, V354, P56 JOURDAIN V, 2004, ADV MATER, V16, P447 JOURDAIN V, 2005, J PHYS CHEM B, V109, P1380 KUO CT, 2003, DIAM RELAT MATER, V12, P799 LEONHARDT A, 2003, DIAM RELAT MATER, V12, P790 LIANG CH, 2000, J CRYST GROWTH, V218, P136 SERAPHIN S, 1993, NATURE, V362, P503 TSANG SC, 1994, NATURE, V372, P159 TSUKAGOSHI K, 1999, NATURE, V401, P572 TSUKAGOSHI K, 2001, MAT SCI ENG B-SOLID, V84, P26 WOLF SA, 2001, SCIENCE, V294, P1488 YANG CK, 2003, PHYS REV LETT, V90 English Article 1520-6106

Résumé:

We have developed a versatile catalyst-assisted chemical vapor deposition (CVD) technique for the synthesis of single-walled carbon nanombes (SWNTs) from discrete nickel nanoparticles (average diameter of 4.7 +/- 1.5 nm). Atomic force microscopy (AFM), transmission electron microscopy (TEM) and electron diffraction are used to characterize these as-grown nanombes. On a particular sample we found that the SWNTs have an average chiral angle of 25.3 degrees. This result shows that a control of the chiral angle of SWNT with large diameters (mean diameter = 1.75 nm) and with a relatively broad diameter distribution (standard deviation = 0.5 nm) is achievable to a certain extent. (c) 2006 Elsevier B.V. All rights reserved.

Ref HAL: hal-00656978_v1
DOI: 10.1016/j.diamond.2005.02.006
WoS: 000230797200003
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15 Citations
Résumé:

We have developed a versatile catalyst-assisted chemical vapor deposition (CVD) technique for the synthesis of single-walled carbon nanotubes (SVNTs) from discrete nickel nanoparticles (average diameter of 4.7 +/- 1.4 nm). Atomic force microscopy (AFM), transmission electron microscopy (TEM) and micro-Raman spectroscopy are used to characterize these as-grown nanotubes. Using a conventional set-up, we are able to produce isolated SWNTs with a narrow diameter distribution (1.5 +/- 0.5 nm). The advantages of such a versatile CVD method for the study of physical properties at the single nanotube level are illustrated by means of two prospective studies on vibrational and electrostatic properties of SWNTs. (c) 2005 Elsevier B.V. All rights reserved.

Ref HAL: hal-00656980_v1
PMID 16851106
DOI: 10.1021/jp046619v
WoS: 000226626500009
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13 Citations
Résumé:

Sequential catalytic growth provides an efficient tool for the synthesis of carbon nanotubes periodically inserted with catalyst nanoparticles. Several synthesis parameters were found crucial in order to induce this particular growth mechanism. The presence of phosphorus is required to form metal phosphide particles active for the formation of carbon nanotubes with a matchstick morphology. The metal composition (Ni/Fe ratio) and the carbon supply have no influence on the nanofilament type but strongly affect the nanotube yield. The synthesis temperature induces important changes on both the nanofilament type and yield, which are correlated with important transformations of the catalyst layer in terms of composition, particle size, and physical state.