Boron nitride cones: structure determination by transmission electron microscopy

Bourgeois, Laure; Bando, Yoshio; Shinozaki, Satoshi; Kurashima, Keiji; Satô, Tadao

doi:10.1107/s0108767398008642

Cited by 49 publications

(36 citation statements)

References 21 publications

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“…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 4mentioning

confidence: 57%

Subangstrom Edge Relaxations Probed by Electron Microscopy in Hexagonal Boron Nitride

et al. 2012

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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.

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

confidence: 57%

Subangstrom Edge Relaxations Probed by Electron Microscopy in Hexagonal Boron Nitride

et al. 2012

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“…The graphitic cones were revealed to consist of a pile of monolayer graphitic cones. Cone shape BN materials were found by Bourgeois et al (1999), whose apex angles ranged from 848 to 1308. They proposed a structural model, in which a conical BN layer is helically wound about the cone axis.…”

Section: Eels Analysis Of a Bn Nanoconementioning

confidence: 99%

Electronic structure analyses of BN network materials using high energy‐resolution spectroscopy methods based on transmission electron microscopy

Terauchi

2006

Microscopy Res & Technique

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Electronic structures of boron-nitride (BN) nanotubes and a BN cone-structure material were studied by using a high energy-resolution electron energy-loss spectroscopy (EELS) microscope. A trial of the whole electronic structure study of hexagonal BN (h-BN), which consists of flat BN honeycomb layers, was conducted by a combination of EELS and X-ray emission spectroscopy (XES) based on transmission electron microscopy (TEM) (TEM-EELS/XES). The pi and pi+sigma plasmon energies of BN nanotubes (BNT) were smaller than those of h-BN. The pi+sigma energy was explained by the surface plasmon excitation. The spectrum of a two-wall BNT of 2.7 nm in diameter showed a new spectral onset at 4 eV. The valence electron excitation spectra obtained from the tip region of the BN cone with an apex angle of 20 degrees showed similar intensity distribution with those of BNTs. The B K-shell electron excitation spectra obtained from the bottom edge region of the BN cone showed additional peak intensity when compared with those of h-BN and BNT. The B K-shell electron excitation spectra and B K-emission spectra of h-BN were compared with a result of a LDA band calculation. It showed that high symmetry points in the band diagram appear as peak and/or shoulder structures in the EELS and XES spectra. Interband transitions appeared in the imaginary part of the dielectric function of h-BN experimentally obtained were assigned in the band diagram. The analysis also presented that the LDA calculation estimated the bandgap energy smaller than the real material by an amount of 2 eV. Those results of TEM-EELS/XES analysis presented that high energy-resolution spectroscopy methods combined with TEM is a promising method to analyze whole electronic structures of nanometer scale materials.

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“…Other characterizations such as high-resolution transmission electron microscopy (HRTEM) or scanning electro microcopy (SEM), which have been described previously [13,14], also could be used for helping to clarify the issue.…”

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confidence: 99%

Letter to Editor

2007

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Boron nitride cones: structure determination by transmission electron microscopy

Cited by 49 publications

References 21 publications

Subangstrom Edge Relaxations Probed by Electron Microscopy in Hexagonal Boron Nitride

Subangstrom Edge Relaxations Probed by Electron Microscopy in Hexagonal Boron Nitride

Electronic structure analyses of BN network materials using high energy‐resolution spectroscopy methods based on transmission electron microscopy

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