Morphological evolution of neodymium boride nanostructure growth by chemical vapor deposition

Gonghua Wang, Joseph R. Brewer, Jie Ying Chan, David R. Diercks, Chin Li "Barry" Cheung

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

Nanoscale-driven design of electron emission materials can significantly increase their overall efficiency as cathodes for field-induced electron emission by taking advantage of the field enhancement effect. The refractory nature and low work function (1.6 eV) of neodymium hexaboride (NdB 6) suggest that high aspect ratio NdB 6 nanostructures are potential candidates as efficient field emission cathodes. Here we report the morphological evolution of one-dimensional neodymium boride nanostructures synthesized using palladium-nanoparticlecatalyzed chemical vapor deposition as a function of reaction temperature. Scanning electron microscopy data show that judicious choices of reaction temperatures (795-940 °C) can lead to the preferential growth of curly nanowires or high aspect ratio nanowires. Transmission electron microscopy and selected area electron diffraction reveal that the crystallinity of these nanostructures changes from amorphous, to polycrystalline, to single crystalline as the reaction temperature increases. At reaction temperatures above 900 °C, single-crystalline NdB 6 nanowires with preferential [100] growth direction were successfully synthesized. Energy dispersive X-ray spectroscopic data suggest that this morphological evolution was strongly influenced by the solubility profiles of Nd and B in the Pd catalyst nanoparticles at different reaction temperatures. The implication of these results on the criteria of catalyst choices for the growth of binary metallic boride nanomaterials is also discussed.

Original languageEnglish (US)
Pages (from-to)10446-10451
Number of pages6
JournalJournal of Physical Chemistry C
Volume113
Issue number24
DOIs
StatePublished - Jun 18 2009

Fingerprint

Boron Compounds
nanostructure growth
Neodymium
borides
Borides
neodymium
Chemical vapor deposition
Nanostructures
vapor deposition
Nanowires
nanowires
Electron emission
high aspect ratio
electron emission
Aspect ratio
Temperature
cathodes
Field emission cathodes
temperature
Crystalline materials

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Energy(all)
  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films

Cite this

Morphological evolution of neodymium boride nanostructure growth by chemical vapor deposition. / Wang, Gonghua; Brewer, Joseph R.; Chan, Jie Ying; Diercks, David R.; Cheung, Chin Li "Barry".

In: Journal of Physical Chemistry C, Vol. 113, No. 24, 18.06.2009, p. 10446-10451.

Research output: Contribution to journalArticle

Wang, Gonghua ; Brewer, Joseph R. ; Chan, Jie Ying ; Diercks, David R. ; Cheung, Chin Li "Barry". / Morphological evolution of neodymium boride nanostructure growth by chemical vapor deposition. In: Journal of Physical Chemistry C. 2009 ; Vol. 113, No. 24. pp. 10446-10451.
@article{2bbf5ce1923c4e5f839a25b828e9f891,
title = "Morphological evolution of neodymium boride nanostructure growth by chemical vapor deposition",
abstract = "Nanoscale-driven design of electron emission materials can significantly increase their overall efficiency as cathodes for field-induced electron emission by taking advantage of the field enhancement effect. The refractory nature and low work function (1.6 eV) of neodymium hexaboride (NdB 6) suggest that high aspect ratio NdB 6 nanostructures are potential candidates as efficient field emission cathodes. Here we report the morphological evolution of one-dimensional neodymium boride nanostructures synthesized using palladium-nanoparticlecatalyzed chemical vapor deposition as a function of reaction temperature. Scanning electron microscopy data show that judicious choices of reaction temperatures (795-940 °C) can lead to the preferential growth of curly nanowires or high aspect ratio nanowires. Transmission electron microscopy and selected area electron diffraction reveal that the crystallinity of these nanostructures changes from amorphous, to polycrystalline, to single crystalline as the reaction temperature increases. At reaction temperatures above 900 °C, single-crystalline NdB 6 nanowires with preferential [100] growth direction were successfully synthesized. Energy dispersive X-ray spectroscopic data suggest that this morphological evolution was strongly influenced by the solubility profiles of Nd and B in the Pd catalyst nanoparticles at different reaction temperatures. The implication of these results on the criteria of catalyst choices for the growth of binary metallic boride nanomaterials is also discussed.",
author = "Gonghua Wang and Brewer, {Joseph R.} and Chan, {Jie Ying} and Diercks, {David R.} and Cheung, {Chin Li {"}Barry{"}}",
year = "2009",
month = "6",
day = "18",
doi = "10.1021/jp901717h",
language = "English (US)",
volume = "113",
pages = "10446--10451",
journal = "Journal of Physical Chemistry C",
issn = "1932-7447",
publisher = "American Chemical Society",
number = "24",

}

TY - JOUR

T1 - Morphological evolution of neodymium boride nanostructure growth by chemical vapor deposition

AU - Wang, Gonghua

AU - Brewer, Joseph R.

AU - Chan, Jie Ying

AU - Diercks, David R.

AU - Cheung, Chin Li "Barry"

PY - 2009/6/18

Y1 - 2009/6/18

N2 - Nanoscale-driven design of electron emission materials can significantly increase their overall efficiency as cathodes for field-induced electron emission by taking advantage of the field enhancement effect. The refractory nature and low work function (1.6 eV) of neodymium hexaboride (NdB 6) suggest that high aspect ratio NdB 6 nanostructures are potential candidates as efficient field emission cathodes. Here we report the morphological evolution of one-dimensional neodymium boride nanostructures synthesized using palladium-nanoparticlecatalyzed chemical vapor deposition as a function of reaction temperature. Scanning electron microscopy data show that judicious choices of reaction temperatures (795-940 °C) can lead to the preferential growth of curly nanowires or high aspect ratio nanowires. Transmission electron microscopy and selected area electron diffraction reveal that the crystallinity of these nanostructures changes from amorphous, to polycrystalline, to single crystalline as the reaction temperature increases. At reaction temperatures above 900 °C, single-crystalline NdB 6 nanowires with preferential [100] growth direction were successfully synthesized. Energy dispersive X-ray spectroscopic data suggest that this morphological evolution was strongly influenced by the solubility profiles of Nd and B in the Pd catalyst nanoparticles at different reaction temperatures. The implication of these results on the criteria of catalyst choices for the growth of binary metallic boride nanomaterials is also discussed.

AB - Nanoscale-driven design of electron emission materials can significantly increase their overall efficiency as cathodes for field-induced electron emission by taking advantage of the field enhancement effect. The refractory nature and low work function (1.6 eV) of neodymium hexaboride (NdB 6) suggest that high aspect ratio NdB 6 nanostructures are potential candidates as efficient field emission cathodes. Here we report the morphological evolution of one-dimensional neodymium boride nanostructures synthesized using palladium-nanoparticlecatalyzed chemical vapor deposition as a function of reaction temperature. Scanning electron microscopy data show that judicious choices of reaction temperatures (795-940 °C) can lead to the preferential growth of curly nanowires or high aspect ratio nanowires. Transmission electron microscopy and selected area electron diffraction reveal that the crystallinity of these nanostructures changes from amorphous, to polycrystalline, to single crystalline as the reaction temperature increases. At reaction temperatures above 900 °C, single-crystalline NdB 6 nanowires with preferential [100] growth direction were successfully synthesized. Energy dispersive X-ray spectroscopic data suggest that this morphological evolution was strongly influenced by the solubility profiles of Nd and B in the Pd catalyst nanoparticles at different reaction temperatures. The implication of these results on the criteria of catalyst choices for the growth of binary metallic boride nanomaterials is also discussed.

UR - http://www.scopus.com/inward/record.url?scp=67650762876&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=67650762876&partnerID=8YFLogxK

U2 - 10.1021/jp901717h

DO - 10.1021/jp901717h

M3 - Article

VL - 113

SP - 10446

EP - 10451

JO - Journal of Physical Chemistry C

JF - Journal of Physical Chemistry C

SN - 1932-7447

IS - 24

ER -