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Title: Diamond nanowires and the insulator-metal transition in ultrananocrystalline diamond films.

Abstract

Further progress in the development of the remarkable electrochemical, electron field emission, high-temperature diode, and optical properties of n-type ultrananocrystalline diamond films requires a better understanding of electron transport in this material. Of particular interest is the origin of the transition to the metallic regime observed when about 10% by volume of nitrogen has been added to the synthesis gas. Here, we present data showing that the transition to the metallic state is due to the formation of partially oriented diamond nanowires surrounded by an sp{sup 2}-bonded carbon sheath. These have been characterized by scanning electron microscopy, transmission electron microscopy techniques (high-resolution mode, selected area electron diffraction, and electron-energy-loss spectroscopy), Raman spectroscopy, and small-angle neutron scattering. The nanowires are 80-100 nm in length and consist of {approx}5 nm wide and 6-10 nm long segments of diamond crystallites exhibiting atomically sharp interfaces. Each nanowire is enveloped in a sheath of sp{sup 2}-bonded carbon that provides the conductive path for electrons. Raman spectroscopy on the films coupled with a consideration of plasma chemical and physical processes reveals that the sheath is likely composed of a nanocarbon material resembling in some respects a polymer-like mixture of polyacetylene and polynitrile. The complex interactions governingmore » the simultaneous growth of the diamond core and the sp{sup 2} sheath responsible for electrical conductivity are discussed as are attempts at a better theoretical understanding of the transport mechanism.« less

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
946413
Report Number(s):
ANL/MSD/JA-58056
Journal ID: ISSN 1098-0121; TRN: US0900951
DOE Contract Number:  
DE-AC02-06CH11357
Resource Type:
Journal Article
Resource Relation:
Journal Name: Phys. Rev. B; Journal Volume: 75; Journal Issue: May 2007
Country of Publication:
United States
Language:
ENGLISH
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; CARBON; DIAMONDS; ELECTRIC CONDUCTIVITY; ELECTRON DIFFRACTION; ELECTRONS; FIELD EMISSION; MIXTURES; NEUTRONS; NITROGEN; OPTICAL PROPERTIES; ORIGIN; POLYACETYLENES; RAMAN SPECTROSCOPY; SCANNING ELECTRON MICROSCOPY; SCATTERING; SPECTROSCOPY; SYNTHESIS GAS; TRANSMISSION ELECTRON MICROSCOPY

Citation Formats

Arenal, R., Bruno, P., Miller, D. J., Bleuel, M., Lai, J., and Gruen, D. M. Diamond nanowires and the insulator-metal transition in ultrananocrystalline diamond films.. United States: N. p., 2007. Web. doi:10.1103/PhysRevB.75.195431.
Arenal, R., Bruno, P., Miller, D. J., Bleuel, M., Lai, J., & Gruen, D. M. Diamond nanowires and the insulator-metal transition in ultrananocrystalline diamond films.. United States. doi:10.1103/PhysRevB.75.195431.
Arenal, R., Bruno, P., Miller, D. J., Bleuel, M., Lai, J., and Gruen, D. M. Tue . "Diamond nanowires and the insulator-metal transition in ultrananocrystalline diamond films.". United States. doi:10.1103/PhysRevB.75.195431.
@article{osti_946413,
title = {Diamond nanowires and the insulator-metal transition in ultrananocrystalline diamond films.},
author = {Arenal, R. and Bruno, P. and Miller, D. J. and Bleuel, M. and Lai, J. and Gruen, D. M.},
abstractNote = {Further progress in the development of the remarkable electrochemical, electron field emission, high-temperature diode, and optical properties of n-type ultrananocrystalline diamond films requires a better understanding of electron transport in this material. Of particular interest is the origin of the transition to the metallic regime observed when about 10% by volume of nitrogen has been added to the synthesis gas. Here, we present data showing that the transition to the metallic state is due to the formation of partially oriented diamond nanowires surrounded by an sp{sup 2}-bonded carbon sheath. These have been characterized by scanning electron microscopy, transmission electron microscopy techniques (high-resolution mode, selected area electron diffraction, and electron-energy-loss spectroscopy), Raman spectroscopy, and small-angle neutron scattering. The nanowires are 80-100 nm in length and consist of {approx}5 nm wide and 6-10 nm long segments of diamond crystallites exhibiting atomically sharp interfaces. Each nanowire is enveloped in a sheath of sp{sup 2}-bonded carbon that provides the conductive path for electrons. Raman spectroscopy on the films coupled with a consideration of plasma chemical and physical processes reveals that the sheath is likely composed of a nanocarbon material resembling in some respects a polymer-like mixture of polyacetylene and polynitrile. The complex interactions governing the simultaneous growth of the diamond core and the sp{sup 2} sheath responsible for electrical conductivity are discussed as are attempts at a better theoretical understanding of the transport mechanism.},
doi = {10.1103/PhysRevB.75.195431},
journal = {Phys. Rev. B},
number = May 2007,
volume = 75,
place = {United States},
year = {Tue May 01 00:00:00 EDT 2007},
month = {Tue May 01 00:00:00 EDT 2007}
}