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Title: The effect of nitrogen incorporation on the bonding structure of hydrogenated carbon nitride films

Abstract

This work describes the composition and bonding structure of hydrogenated carbon nitride (a-CN{sub x}:H) films synthesized by electron cyclotron resonance chemical vapor deposition using as precursor gases argon, methane, and nitrogen. The composition of the films was derived from Rutherford backscattering and elastic recoil detection analysis and the bonding structure was examined by infrared (IR) spectroscopy and x-ray absorption near edge spectroscopy (XANES). By varying the nitrogen to methane ratio in the applied gas mixture, polymeric a-CN{sub x}:H films with N/C contents varying from 0.06 to 0.49 were obtained. Remarkably, the H content of the films ({approx}40 at. %) was rather unaffected by the nitrogenation process. The different bonding states as detected in the measured XANES C(1s) and N(1s) spectra have been correlated with those of a large number of reference samples. The XANES and IR spectroscopy results indicate that N atoms are efficiently incorporated into the amorphous carbon network and can be found in different bonding environments, such as pyridinelike, graphitelike, nitrilelike, and amino groups. The nitrogenation of the films results in the formation of N-H bonding environments at the cost of C-H structures. Also, the insertion of N induces a higher fraction of double bonds in the structuremore » at the expense of the linear polymerlike chains, hence resulting in a more cross-linked solid. The formation of double bonds takes place through complex C=N structures and not by formation of graphitic aromatic rings. Also, the mechanical and tribological properties (hardness, friction, and wear) of the films have been studied as a function of the nitrogen content. Despite the major modifications in the bonding structure with nitrogen uptake, no significant changes in these properties are observed.« less

Authors:
; ; ; ; ;  [1];  [2];  [3];  [4];  [5]
  1. Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), C/ Sor Juana Ines de la Cruz 3, Cantoblanco, 28049 Madrid (Spain)
  2. (CMAM) and Departamento de Fisica Aplicada, Universidad Autonoma de Madrid, C/ Faraday 3, Cantoblanco, 28049 Madrid (Spain)
  3. (Belgium)
  4. (ICMM-CSIC), C/ Sor Juana Ines de la Cruz 3, Cantoblanco, 28049 Madrid (Spain)
  5. (ICTP-CSIC), Juan de la Cierva 3, 28006 Madrid (Spain)
Publication Date:
OSTI Identifier:
20982755
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 101; Journal Issue: 6; Other Information: DOI: 10.1063/1.2712142; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ABSORPTION; ABSORPTION SPECTROSCOPY; AMORPHOUS STATE; ARGON; BOUND STATE; CARBON NITRIDES; CHEMICAL VAPOR DEPOSITION; DOUBLE BONDS; ELECTRON CYCLOTRON-RESONANCE; FRICTION; GRAPHITE; HARDNESS; HYDROGEN; INFRARED SPECTRA; METHANE; NITROGEN; RUTHERFORD BACKSCATTERING SPECTROSCOPY; THIN FILMS; X-RAY SPECTROSCOPY

Citation Formats

Camero, M., Buijnsters, J. G., Gomez-Aleixandre, C., Gago, R., Caretti, I., Jimenez, I., Centro de Micro-Analisis de Materiales, Department of Physics, University of Antwerp, Campus Drie Eiken, Universiteitsplein 1, 2610 Wilrijk, Instituto de Ciencia de Materiales de Madrid, and Instituto de Ciencia y Tecnologia de Polimeros. The effect of nitrogen incorporation on the bonding structure of hydrogenated carbon nitride films. United States: N. p., 2007. Web. doi:10.1063/1.2712142.
Camero, M., Buijnsters, J. G., Gomez-Aleixandre, C., Gago, R., Caretti, I., Jimenez, I., Centro de Micro-Analisis de Materiales, Department of Physics, University of Antwerp, Campus Drie Eiken, Universiteitsplein 1, 2610 Wilrijk, Instituto de Ciencia de Materiales de Madrid, & Instituto de Ciencia y Tecnologia de Polimeros. The effect of nitrogen incorporation on the bonding structure of hydrogenated carbon nitride films. United States. doi:10.1063/1.2712142.
Camero, M., Buijnsters, J. G., Gomez-Aleixandre, C., Gago, R., Caretti, I., Jimenez, I., Centro de Micro-Analisis de Materiales, Department of Physics, University of Antwerp, Campus Drie Eiken, Universiteitsplein 1, 2610 Wilrijk, Instituto de Ciencia de Materiales de Madrid, and Instituto de Ciencia y Tecnologia de Polimeros. Thu . "The effect of nitrogen incorporation on the bonding structure of hydrogenated carbon nitride films". United States. doi:10.1063/1.2712142.
@article{osti_20982755,
title = {The effect of nitrogen incorporation on the bonding structure of hydrogenated carbon nitride films},
author = {Camero, M. and Buijnsters, J. G. and Gomez-Aleixandre, C. and Gago, R. and Caretti, I. and Jimenez, I. and Centro de Micro-Analisis de Materiales and Department of Physics, University of Antwerp, Campus Drie Eiken, Universiteitsplein 1, 2610 Wilrijk and Instituto de Ciencia de Materiales de Madrid and Instituto de Ciencia y Tecnologia de Polimeros},
abstractNote = {This work describes the composition and bonding structure of hydrogenated carbon nitride (a-CN{sub x}:H) films synthesized by electron cyclotron resonance chemical vapor deposition using as precursor gases argon, methane, and nitrogen. The composition of the films was derived from Rutherford backscattering and elastic recoil detection analysis and the bonding structure was examined by infrared (IR) spectroscopy and x-ray absorption near edge spectroscopy (XANES). By varying the nitrogen to methane ratio in the applied gas mixture, polymeric a-CN{sub x}:H films with N/C contents varying from 0.06 to 0.49 were obtained. Remarkably, the H content of the films ({approx}40 at. %) was rather unaffected by the nitrogenation process. The different bonding states as detected in the measured XANES C(1s) and N(1s) spectra have been correlated with those of a large number of reference samples. The XANES and IR spectroscopy results indicate that N atoms are efficiently incorporated into the amorphous carbon network and can be found in different bonding environments, such as pyridinelike, graphitelike, nitrilelike, and amino groups. The nitrogenation of the films results in the formation of N-H bonding environments at the cost of C-H structures. Also, the insertion of N induces a higher fraction of double bonds in the structure at the expense of the linear polymerlike chains, hence resulting in a more cross-linked solid. The formation of double bonds takes place through complex C=N structures and not by formation of graphitic aromatic rings. Also, the mechanical and tribological properties (hardness, friction, and wear) of the films have been studied as a function of the nitrogen content. Despite the major modifications in the bonding structure with nitrogen uptake, no significant changes in these properties are observed.},
doi = {10.1063/1.2712142},
journal = {Journal of Applied Physics},
number = 6,
volume = 101,
place = {United States},
year = {Thu Mar 15 00:00:00 EDT 2007},
month = {Thu Mar 15 00:00:00 EDT 2007}
}
  • No abstract prepared.
  • Carbon (C) and carbon nitride (CN{sub x}) films were grown on Si(100) substrates by direct ion-beam sputtering (IBS) of a carbon target at different substrate temperatures (room temperature-450 deg. C) and Ar/N{sub 2} sputtering gas mixtures. Additionally, the effect of concurrent nitrogen-ion assistance during the growth of CN{sub x} films by IBS was also investigated. The samples were analyzed by elastic recoil detection analysis (ERDA) and x-ray absorption near-edge spectroscopy (XANES). The ERDA results showed that significant nitrogen amount (up to 20 at. %) was incorporated in the films, without any other nitrogen source but the N{sub 2}-containing sputtering gas.more » The nitrogen concentration is proportional to the N{sub 2} content in the sputtering beam and no saturation limit is reached under the present working conditions. The film areal density derived from ERDA revealed a decrease in the amount of deposited material at increasing growth temperature, with a correlation between the C and N losses. The XANES results indicate that N atoms are efficiently incorporated into the carbon network and can be found in different bonding environments, such as pyridinelike, nitrilelike, graphitelike, and embedded N{sub 2} molecules. The contribution of molecular and pyridinelike nitrogen decreases when the temperature increases while the contribution of the nitrilelike nitrogen increases. The concurrent nitrogen ion assistance resulted in the significant increase of the nitrogen content in the film but it induced a further reduction of the deposited material. Additionally, the assisting ions inhibited the formation of the nitrilelike configurations while promoting nitrogen environments in graphitelike positions. The nitrogen incorporation and release mechanisms are discussed in terms of film growth precursors, ion bombardment effects, and chemical sputtering.« less
  • Hydrogenated amorphous carbon (a-C:H) thin films were deposited on silicon single crystal substrates from toluene vapor using rf plasma at room temperature. After deposition, the a-C:H films were irradiated with a nitrogen ion beam and effects of nitrogen ion beam irradiation on surface morphology and composition were studied. Nitrogen ion irradiation was performed using nitrogen ion beams of 0.2 and 1.5 keV for 10 min under the constant ion current density at room temperature. Surface morphology was observed by atomic force microscopy (AFM). Changes in composition and carbon-nitrogen bonding states were analyzed by x-ray photoelectron spectroscopy (XPS). Carbon structures weremore » examined by Raman spectroscopy. AFM observations revealed that the film surface became smooth after nitrogen ion beam irradiation and a notable difference in surface roughness is hardly observed between 0.2 and 1.5 keV ion irradiation. XPS studies showed that nitrogen was implanted near the surface of the a-C:H films after nitrogen ion irradiation and combined with carbon, resulting in carbon nitride formation. Depth profiles obtained by XPS showed that nitrogen ions were implanted in the a-C:H films more deeply after 1.5 keV ion irradiation than 0.2 keV ion irradiation. The implanted nitrogen ion behavior inside the films has been clarified, which is useful to judge the effectiveness for the formation of carbon nitride layers. Carbon structures did not change remarkably after nitrogen ion irradiation except the surface region, where carbon nitride layers are formed.« less
  • The bonding structure of highly ordered fullerenelike (FL) carbon nitride (CN{sub x}) thin films has been assessed by x-ray absorption near-edge spectroscopy (XANES). Samples with different degrees of FL character have been analyzed to discern spectral signatures related to the FL microstructure. The XANES spectra of FL-CN{sub x} films resemble that of graphitic CN{sub x}, evidencing the sp{sup 2} hybridization of both C and N atoms. The FL structure is achieved with the promotion of N in threefold positions over pyridinelike and cyanidelike bonding environments. In addition, the relative {pi}{sup *}/{sigma}* XANES intensity ratio at the C(1s) edge is independentmore » of the FL character, while it decreases {approx}40% at the N(1s) edge with the formation of FL arrangements. This result indicates that there is no appreciable introduction of C-sp{sup 3} hybrids with the development of FL structures and, additionally, that a different spatial localization of {pi} electrons at C and N sites takes place in curved graphitic structures. The latter has implications for the elastic properties of graphene sheets and could, as such, explain the outstanding elastic properties of FL-CN{sub x}.« less
  • X-ray absorption near edge structure (XANES) was used to investigate two sets of graphite-like BC{sub x}N thin films with similar B:C:N ratios but different amounts of nitrogen vacancies, which become oxygen-filled in the surface-most region. The two sets of samples were grown on Si (100) at room temperature by ion beam assisted deposition using two different ion/atom ratios. Nitrogen vacancy defects were detected in the B1s XANES spectra due to an oxygen decoration mechanism taking place at the film surface, which is correctly described by a core-level shift model. Analysis of the O1s XANES spectra showed two different types ofmore » oxygen incorporation in the samples under study. The tribomechanical properties of the BC{sub x}N samples were tested by the pin-on-disk technique, revealing the substantial role played by both the carbon intake in the hexagonal BCN planes and the concentration of nitrogen vacancies generated during the growth.« less