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Structures carbonées de basses dimensionnalité
(11) Production(s) de l'année 2017
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High temperature annealing and CVD growth of few-layer graphene on bulk AlN and AlN templates
Auteur(s): Dagher R., Matta S., Parret R., Paillet M., Jouault B., Nguyen L., Portail M., Zielinski M., Chassagne T., Tanaka S., Brault J., Cordier Y., Michon A.
(Article) Publié:
Physica Status Solidi A, vol. 214 p.1600436 (2017)
Ref HAL: hal-01563258_v1
DOI: 10.1002/pssa.201600436
WoS: WOS:000402158300006
Exporter : BibTex | endNote
6 Citations
Résumé: Graphene and AlN are promising materials, interesting to combine together. In this study, we will present first results for direct growth of graphene on bulk AlN and on AlN templates using chemical vapor deposition, including the annealing of these substrates at high temperatures. Atomic force microscopy (AFM) enabled us to study the evolution of the AlN surface morphology after annealing and growth. Few-layer graphene deposition is demonstrated on the basis of X-ray photoemission and Raman spectroscopy
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Quantum interference effects on the intensity of the G modes in double-walled carbon nanotubes
Auteur(s): Tran H.-N., Blancon J.-C., Arenal R., Parret R., Zahab A. A., Ayari Anthony, Vallee F., del Fatti N., Sauvajol J.-L., Paillet M.
(Article) Publié:
Physical Review B, vol. 95 p.205411 (2017)
Texte intégral en Openaccess :
Ref HAL: hal-01542689_v1
DOI: 10.1103/PhysRevB.95.205411
WoS: WOS:000401230300010
Exporter : BibTex | endNote
4 Citations
Résumé: The effects of quantum interferences on the excitation dependence of the intensity of G modes have beeninvestigated on single-walled carbon nanotubes [Duque et al., Phys. Rev. Lett. 108, 117404 (2012)]. In this work,by combining optical absorption spectroscopy and Raman scattering on individual index identified double-walledcarbon nanotubes, we examine the experimental excitation dependence of the intensity of longitudinal opticaland transverse optical G modes of the constituent inner and outer single-walled carbon nanotubes. The observedstriking dependencies are understood in terms of quantum interference effects. Considering such effects, the excitation dependence of the different components of the G modes permits us to unambiguously assign each ofthem as originating from the longitudinal or transverse G modes of inner and outer tubes.
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Growth of low doped monolayer graphene on SiC(0001) viasublimation at low argon pressure
Auteur(s): Landois P., Wang T., Nachawaty A., Bayle M., Decams J.M., Desrat W., Zahab A. A., Jouault B., Paillet M., Contreras S.
(Article) Publié:
Physical Chemistry Chemical Physics, vol. p.10.1039/c7cp01012e (2017)
Ref HAL: hal-01540335_v1
DOI: 10.1039/c7cp01012e
WoS: 000403965500023
Exporter : BibTex | endNote
5 Citations
Résumé: Silicon carbide (SiC) sublimation is the most promising option to achieve transfer-free graphene at the wafer-scale. We investigated the initial growth stages from the buffer layer to monolayer graphene on SiC(0001) as a function of annealing temperature at low argon pressure (10 mbar). A buffer layer, fully covering the SiC substrate, forms when the substrate is annealed at 1600°C. Graphene formation starts from the step edges of the SiC substrate at higher temperature (1700°C). The spatial homogeneity of the monolayer graphene was observed at 1750°C, as characterized by Raman spectroscopy and magneto-transport. Raman spectroscopy mapping indicated an AG-graphene/AG-HOPG ratio of around 3.3%, which is very close to the experimental value reported for a graphene monolayer. Transport measurements fromroom temperature down to 1.7 K indicated slightly p-doped samples (p~10^10cm-2) and confirmed both continuity and thickness of the monolayer graphene film. Successive growth processes have confirmed the reproducibility and homogeneity of these monolayer films.
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Accurate determination of the chiral indices of individual carbon nanotubes by combining electron diffraction and Resonant Raman spectroscopy
Auteur(s): Levshov D., Tran H.-N., Paillet M., Arenal R., Than X. T., Zahab A. A., Yuzyuk Y. I., Sauvajol J.-L., Michel T.
(Article) Publié:
Carbon, vol. 114 p.141-159 (2017)
Texte intégral en Openaccess :
Ref HAL: hal-01500547_v1
DOI: 10.1016/j.carbon.2016.11.076
WoS: WOS:000393249600018
Exporter : BibTex | endNote
19 Citations
Résumé: The experimental approach combining high resolution transmission electron microscopy (HRTEM), electron diffraction (ED) and resonant Raman spectroscopy (RRS) on the same free-standing individual carbon nanotubes (CNT) is the most efficient method to determine unambiguously the intrinsic features of the Raman-active phonons. In this paper, we review the main results obtained by the approach regarding the intrinsic features of the phonons of single-walled (SWNT) and double-walled carbon nanotubes (DWNT). First, we detail the different methods to identify the structure of SWNTs and DWNTs from the analysis of their electron diffraction patterns (EDP). In the following, we remind the principal features of the Raman response of SWNTs, unambiguously index-identified by ED. A special attention is devoted to the effect of the inter-layer interaction on the frequencies of the Raman-active phonons in index-identified DWNTs. The information obtained on index-identified SWNT and DWNT allows us to propose Raman criteria, which help identifying CNT when the ED fails to propose a single assignment. The efficiency of the Raman criteria as the complement to the ED information for the index-assignment of a few SWNTs and DWNTs is shown. The same approach to index-assign a triple-walled carbon nanotube (TWNT), by combining ED and RRS information, is reported.
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