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Title: Clustering in a highly hydrogenated diamondlike carbon determined using fluctuation electron microscopy and phenomenological atomistic simulations.

Abstract

We compare fluctuation electron microscopy data to simulations from phenomenological atomic models and demonstrate a strong correspondence between some features in the experimental data and certain atomic configurations. This allows the nature of atomic clustering in a highly hydrogenated diamondlike carbon to be determined more closely. We compare the structural information garnered from fluctuation electron microscopy and Raman spectroscopy for a particular diamondlike carbon and find consistency between the two techniques in the region where their information overlaps.

Authors:
; ; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
915030
Report Number(s):
ANL/MSD/JA-59785
Journal ID: ISSN 0163-1829; PRBMDO; TRN: US0804883
DOE Contract Number:
DE-AC02-06CH11357
Resource Type:
Journal Article
Resource Relation:
Journal Name: Phys. Rev. B; Journal Volume: 76; Journal Issue: 2007
Country of Publication:
United States
Language:
ENGLISH
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; ATOMIC MODELS; CARBON; ELECTRON MICROSCOPY; FLUCTUATIONS; RAMAN SPECTROSCOPY

Citation Formats

Liu, A. C. Y., Arenal, R., Chen, X., Materials Science Division, and ONERA-CNRS. Clustering in a highly hydrogenated diamondlike carbon determined using fluctuation electron microscopy and phenomenological atomistic simulations.. United States: N. p., 2007. Web. doi:10.1103/PhysRevB.76.121401.
Liu, A. C. Y., Arenal, R., Chen, X., Materials Science Division, & ONERA-CNRS. Clustering in a highly hydrogenated diamondlike carbon determined using fluctuation electron microscopy and phenomenological atomistic simulations.. United States. doi:10.1103/PhysRevB.76.121401.
Liu, A. C. Y., Arenal, R., Chen, X., Materials Science Division, and ONERA-CNRS. Mon . "Clustering in a highly hydrogenated diamondlike carbon determined using fluctuation electron microscopy and phenomenological atomistic simulations.". United States. doi:10.1103/PhysRevB.76.121401.
@article{osti_915030,
title = {Clustering in a highly hydrogenated diamondlike carbon determined using fluctuation electron microscopy and phenomenological atomistic simulations.},
author = {Liu, A. C. Y. and Arenal, R. and Chen, X. and Materials Science Division and ONERA-CNRS},
abstractNote = {We compare fluctuation electron microscopy data to simulations from phenomenological atomic models and demonstrate a strong correspondence between some features in the experimental data and certain atomic configurations. This allows the nature of atomic clustering in a highly hydrogenated diamondlike carbon to be determined more closely. We compare the structural information garnered from fluctuation electron microscopy and Raman spectroscopy for a particular diamondlike carbon and find consistency between the two techniques in the region where their information overlaps.},
doi = {10.1103/PhysRevB.76.121401},
journal = {Phys. Rev. B},
number = 2007,
volume = 76,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}
  • Electron spin resonance (ESR) measurements on diamondlike carbon films show that the as-grown material possesses a very high (2.5 x 10/sup 20/ cm/sup -3/) concentration of dangling bonds. Upon irradiation with 50-keV C/sup +/ carbon ions, the number of ESR active centers increases by a factor of 3.5 and the linewidth narrows, but no shift in the g value is observed, and the resonant peak remains Lorentzian. These effects are concomitant with the previously observed dramatic decrease in the electrical resistivity (4--5 orders of magnitude). The ESR results verify that no graphitelike islands have formed as a result of themore » irradiation. The likely conduction mechanism is via hopping in band tail states, the number of which increases as a result of the ion impact.« less
  • Oxygen-incorporated hydrogenated amorphous carbon films were grown by the integrated distributed electron cyclotron resonance plasma technique from a mixture of acetylene and oxygen. It has been found that the increase of the oxygen to acetylene gas ratio results in more oxygen incorporation up to O/(O+C)=0.2 with a decrease in the hydrogen concentration within the film as measured by the nuclear reaction analysis (NRA) and a combination of the elastic recoil detection analysis and Rutherford backscattering techniques. The spectroscopic ellipsometry in the range of 1.5-5 eV showed a negligible decrease of the E{sub 04} optical band gap for increasing the oxygenmore » content. At the same time, the decrease of the refractive index from 2.2 to 2.0 denotes the decrease of the films density, which was independently estimated by NRA. The visible (488 nm) Raman spectroscopy showed that the increase of the oxygen content favors the clustering of the six-fold sp{sup 2}C rings. The Fourier transform infrared spectroscopy gives evidence of both C-O and C=O bonding configurations. No evidence of O-H bonds formation is found. Simultaneously, the chemisorption of CO{sub 2} seems to increased with increasing the oxygen to acetylene gas ratio, which is consistent with the lower film density. The previously trends denote the 'softening' of the films, which is consistent with the significant decrease (of about 35%) of the compressive stress allowing the growth of thicker but still transparent films.« less
  • Multiwavelength Raman spectroscopy has been used to study the structure of hydrogenated amorphous carbon films synthesized by plasma-enhanced chemical vapor deposition. The analysis of different parameters from the Raman spectra demonstrates that the diameter, structural, and topological orders of the sp{sup 2}-bonded ring clusters increase with increasing fractions of hydrogen in the source gas. We report the existence of an unusual peak at 867 cm{sup -1} that in such extended clusters of aromatic rings, could correspond to a graphitic mode activated by a relaxation of the phonon selection-rule resulting from defects.
  • Multiwavelength Raman spectroscopy has been used to study the structure of hydrogenated amorphous carbon films synthesized by plasma-enhanced chemical vapor deposition. The analysis of different parameters from the Raman spectra demonstrates that the diameter, structural, and topological orders of the sp{sup 2}-bonded ring clusters increase with increasing fractions of hydrogen in the source gas. We report the existence of an unusual peak at 867 cm{sup -1} that in such extended clusters of aromatic rings, could correspond to a graphitic mode activated by a relaxation of the phonon selection-rule resulting from defects.
  • We have studied the electron emission behavior of the diamondlike carbon (DLC) films by plasma enhanced chemical vapor deposition using a layer-by-layer deposition, in which the deposition of a thin layer of DLC and a CF{sub 4} plasma exposure on its surface were carried out alternatively. The electron emission current increases with CF{sub 4} plasma exposure time. The increase in emission current appears to be due to the n-type behavior of the DLC. {copyright} {ital 1997 American Institute of Physics.}