Mapping defects in a carbon nanotube by momentum transfer dependent electron energy loss spectromicroscopy

Najafi, Ebrahim; Hitchcock, Adam P.; Rossouw, David; Botton, Gianluigi A.

doi:10.1016/j.ultramic.2011.11.017

Cited by 19 publications

(16 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Such structural distortions can significantly transform the electronic properties of h-BN flakes. Our spectroscopy results suggest an enhanced probability at the distortion for electrons to transition to Ã orbitals when excited, a behavior previously observed in carbon nanotubes and boron nitride sheets [16,[20][21][22]. Although h-BN nanoribbons are predicted to show a metallic behavior locally at open edges, we demonstrate here that distortions arising from the covalent interlayer bonds across the bilayer h-BN can recover the insulating character of bulk bilayer h-BN.…”

Section: P H Y S I C a L R E V I E W L E T T E R S 4supporting

confidence: 77%

“…In addition, it might further suggest an enhanced preference for electrons to undergo transitions to Ã orbitals at the distortion as compared to the middle of the membrane. Such behavior is also observed around the curved walls of carbon nanotubes at large collection angles [15,16]. The geometry of the reconstructed edge of a bilayer h-BN sheet could be compared locally to a BN nanotube with an extremely short radius of curvature.…”

Section: P H Y S I C a L R E V I E W L E T T E R S 3mentioning

confidence: 89%

See 1 more Smart Citation

Subangstrom Edge Relaxations Probed by Electron Microscopy in Hexagonal Boron Nitride

et al. 2012

View full text Add to dashboard Cite

Theoretical research on the two-dimensional crystal structure of hexagonal boron nitride (h-BN) 2 has suggested that the physical properties of hBN can be tailored for a wealth of applications by controlling the atomic structure of the membrane edges. Unexplored for hBN, however, is the possibility that small additional edge-atom distortions could have electronic structure implications critically important to nanoengineering efforts. Here we demonstrate, using a combination of analytical scanning transmission electron microscopy and density functional theory, that covalent interlayer bonds form spontaneously at the edges of a h-BN bilayer, resulting in subangstrom distortions of the edge atomic structure. Orbital maps calculated in 3D around the closed edge reveal that the out-of-plane bonds retain a strong Ã character. We show that this closed edge reconstruction, strikingly different from the equivalent case for graphene, helps the material recover its bulklike insulating behavior and thus largely negates the predicted metallic character of open edges.

show abstract

Section: P H Y S I C a L R E V I E W L E T T E R S 4supporting

confidence: 77%

Section: P H Y S I C a L R E V I E W L E T T E R S 3mentioning

confidence: 89%

Subangstrom Edge Relaxations Probed by Electron Microscopy in Hexagonal Boron Nitride

et al. 2012

View full text Add to dashboard Cite

show abstract

“…identification of features due to retardation losses, band gaps, interband transitions, surface and volume plasmons, 12 as well as identifying local changes in molecular orbital hybridization. 13 Examples of applications in the electron microscope include the mapping of defects in carbon nanotubes (CNTs), 13 the identification of guided light modes in graphite, 14 the investigation of the electronic structure of ZnO nanowires, 11 as well as the determination of dipole-forbidden transitions in BaBiO 3 (Ref. 15) and NiO.…”

Section: Introductionmentioning

confidence: 99%

Topologically induced confinement of collective modes in multilayer graphene nanocones measured by momentum-resolved STEM-VEELS

et al. 2013

View full text Add to dashboard Cite

In the expanding field of plasmonics, accurate control of the degree of plasmon localization is of crucial importance for tailoring optical properties at the nanoscale. In this paper, the degree of plasmon localization is directly probed by recording the momentum transfer dependence (i.e. the dispersion) of plasmon resonance energies using electron energy loss spectroscopy in the aberration-corrected scanning transmission electron microscope. Limited by the uncertainty principle, resolution in momentum space can easily be tuned by the beam convergence, and it is shown that localization is clearly identifiable, even at low-momentum resolution. In this proof-of-principle study, this technique was applied to multilayer graphene cones containing a varying number of topological defects at their apex. It is shown that a high degree of confinement of the π and π + σ volume plasmons is reached for five pentagonal defects at the cone apex. This effect was attributed to the presence of the topological defects themselves. Furthermore, slight negative refraction was observed for the five-pentagon cone, predominantly affecting the collective excitation of the π electrons.

show abstract

“…While momentum-resolved STEM-EELS of the carbon K ionization edge has been used to map defects in individual multiwalled CNTs [28], this work is a report on plasmon dispersions acquired from individual SWCNTs using EELS. In contrast to methods where the spectroscopic signal is acquired from SWCNT "bulk samples" [5][6][7][8], STEM-EELS allows uniquely for the characterization of the electronic structure and plasmon dispersions as a function of both the chirality of individual SWCNTs and the possible presence of (atomic-sized) defects in the tubes.…”

Section: Introductionmentioning

confidence: 99%

Momentum- and space-resolved high-resolution electron energy loss spectroscopy of individual single-wall carbon nanotubes

et al. 2017

View full text Add to dashboard Cite

The ability to probe the electronic structure of individual nano-objects at high energy resolution using momentum-and space-resolved electron energy loss spectroscopy in the scanning transmission electron microscope is demonstrated through the observation of confinement of the π plasmon in individual single-wall carbon nanotubes. While confinement perpendicular to the tube axis was identified for all investigated tubes, a variable degree of confinement parallel to the tube axis was attributed to the concentration of topological defects. Spatially resolved valence loss spectra allowed for the identification of a loss peak attributed to a chirality-dependent radial interband transition. Furthermore, the importance of a careful consideration of loss peak momentum dispersions for the interpretation of spatially resolved valence loss spectra is discussed.

show abstract

Mapping defects in a carbon nanotube by momentum transfer dependent electron energy loss spectromicroscopy

Cited by 19 publications

References 32 publications

Subangstrom Edge Relaxations Probed by Electron Microscopy in Hexagonal Boron Nitride

Subangstrom Edge Relaxations Probed by Electron Microscopy in Hexagonal Boron Nitride

Topologically induced confinement of collective modes in multilayer graphene nanocones measured by momentum-resolved STEM-VEELS

Momentum- and space-resolved high-resolution electron energy loss spectroscopy of individual single-wall carbon nanotubes

Contact Info

Product

Resources

About