The Experts below are selected from a list of 309 Experts worldwide ranked by ideXlab platform

Alex Zettl - One of the best experts on this subject based on the ideXlab platform.

  • Longitudinal Splitting of Boron Nitride Nanotubes for the Facile Synthesis of High Quality Boron Nitride Nanoribbons
    Nano letters, 2011
    Co-Authors: Kristopher J. Erickson, Ashley L. Gibb, Alexander Sinitskii, Michael Rousseas, Nasim Alem, James M. Tour, Alex Zettl
    Abstract:

    Boron Nitride nanoribbons (BNNRs), the Boron Nitride structural equivalent of graphene nanoribbons (GNRs), are predicted to possess unique electronic and magnetic properties. We report the synthesis of BNNRs through the potassium-intercalation-induced longitudinal splitting of Boron Nitride nanotubes (BNNTs). This facile, scalable synthesis results in narrow (down to 20 nm), few sheet (typically 2-10), high crystallinity BNNRs with very uniform widths. The BNNRs are at least 1 μm in length with minimal defects within the ribbon plane and along the ribbon edges.

  • Symmetry Breaking in Boron Nitride Nanotubes
    Physical review letters, 2006
    Co-Authors: Masa Ishigami, Jay Deep Sau, Shaul Aloni, Marvin L. Cohen, Alex Zettl
    Abstract:

    We have imaged Boron Nitride nanotubes with atomic scale resolution using scanning tunneling microscopy. While some nanotubes show the expected triangular lattice pattern, the majority of the nanotubes show unusual stripe patterns which break the underlying symmetry of the Boron Nitride lattice. We identify the origin of the symmetry breaking and demonstrate that conventional STM imaging analysis is inadequate for Boron Nitride nanotubes.

  • Isotope effect on the thermal conductivity of Boron Nitride nanotubes.
    Physical review letters, 2006
    Co-Authors: Chih-wei Chang, A. M. Fennimore, A. Afanasiev, David Okawa, Takashi Ikuno, Hernan G. Garcia, Arun Majumdar, Alex Zettl
    Abstract:

    We have measured the temperature-dependent thermal conductivity $\ensuremath{\kappa}(T)$ of individual multiwall Boron Nitride nanotubes using a microfabricated test fixture that allows direct transmission electron microscopy characterization of the tube being measured. $\ensuremath{\kappa}(T)$ is exceptionally sensitive to isotopic substitution, with a 50% enhancement in $\ensuremath{\kappa}(T)$ resulting for Boron Nitride nanotubes with 99.5% $^{11}\mathrm{B}$. For isotopically pure Boron Nitride nanotubes, $\ensuremath{\kappa}$ rivals that of carbon nanotubes of similar diameter.

Laurence Goux-capes - One of the best experts on this subject based on the ideXlab platform.

  • Optical Transitions in Single-Wall Boron Nitride Nanotubes
    Physical review letters, 2005
    Co-Authors: Jean-sébastien Lauret, Raul Arenal, François Ducastelle, Annick Loiseau, M. Cau, Brigitte Attal-trétout, Emmanuel Rosencher, Laurence Goux-capes
    Abstract:

    Optical transitions in single-wall Boron Nitride nanotubes are investigated by means of optical absorption spectroscopy. Three absorption lines are observed. Two of them (at 4.45 and 5.5 eV) result from the quantification involved by the rolling up of the hexagonal Boron Nitride (h-BN) sheet. The nature of these lines is discussed, and two interpretations are proposed. A comparison with single-wall carbon nanotubes leads one to interpret these lines as transitions between pairs of van Hove singularities in the one-dimensional density of states of Boron Nitride single-wall nanotubes. But the confinement energy due to the rolling up of the h-BN sheet cannot explain a gap width of the Boron Nitride nanotubes below the h-BN gap. The low energy line is then attributed to the existence of a Frenkel exciton with a binding energy in the 1 eV range.

Jean-louis Sauvajol - One of the best experts on this subject based on the ideXlab platform.

  • Infrared spectrum of single-walled Boron Nitride nanotubes
    Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2012
    Co-Authors: B. Fakrach, A. Rahmani, H. Chadli, K. Sbai, M. Bentaleb, Jean-louis Bantignies, Jean-louis Sauvajol
    Abstract:

    Using the spectral moment's method, the infrared spectra of single-walled Boron Nitride nanotubes are calculated. The dependence of these modes has been calculated as a function of the nanotube chirality, diameter (from 0.7 to 5 nm), and length. These predictions are useful for understanding the experimental infrared spectra of Boron Nitride nanotubes.

Valentin N. Popov - One of the best experts on this subject based on the ideXlab platform.

  • Lattice dynamics of single-walled Boron Nitride nanotubes
    Physical Review B, 2003
    Co-Authors: Valentin N. Popov
    Abstract:

    The phonon dispersion of single-walled Boron Nitride nanotubes is calculated within a valence shell model of the lattice dynamics. The model parameters are derived from fittings to the measured phonon dispersion of hexagonal Boron Nitride and available optical data. The calculated phonon dispersion curves for the tubes $(10,10),$ $(17,0),$ and $(15,4)$ are presented. An analysis of the vibrational patterns of the zone-center phonons is given. The results for the phonon dispersion, zone-center phonons, and nonresonant Raman intensity can be used for the needs of characterization of Boron Nitride nanotube samples by Raman scattering and infrared spectroscopies.

Chengchun Tang - One of the best experts on this subject based on the ideXlab platform.

  • In-situ conversion of porous Boron Nitride to highly crystallized nanoplates-assembled hexagonal Boron Nitride nanoarchitectures via a metal ion-assisted annealing method
    Journal of Alloys and Compounds, 2017
    Co-Authors: Jianli Liang, Yang Huang, Jing Lin, Congcong Feng, Zhiyi Yan, Wei Zhai, Chengchun Tang
    Abstract:

    Abstract We report on the synthesis of novel Boron Nitride nanoarchitectures through in-situ conversion of porous Boron Nitride via a metal ion-assisted annealing method. Numerous highly crystallized nanoplates with thickness of ∼20 nm aggregate as building blocks to form the Boron Nitride nanoarchitecture. The adsorption of low concentration of metal ions, i.e. terbium ions, plays an important role for the in-situ conversion of porous Boron Nitride microfibers to nanoarchitectures. Owing to their unique microstructure with rough surfaces, the as-prepared Boron Nitride nanoarchitectures show superhydrophobicity with a high contact angle of 167.9°. Photoluminescence studies indicate that the nanoarchitectures exhibit intense ultraviolet emission from Boron Nitride nanostructures and green emission from terbium ions. The combination of unique microstructures and properties enables Boron Nitride nanoarchitectures to be attractive for applications in catalytic support and self-cleaning coatings.

  • Functional Boron Nitride nanotubes
    Nanoelectronics Conference INEC 2010 3rd International, 2010
    Co-Authors: Dimitri Golberg, Chengchun Tang, Yoshio Bando, Chunyi Zhi
    Abstract:

    We describe synthesis, property investigations and composite applications of multi-walled Boron Nitride nanotubes.

  • Irreversible pressure-induced transformation of Boron Nitride nanotubes.
    Journal of nanoscience and nanotechnology, 2007
    Co-Authors: Surajit Saha, Chengchun Tang, Yoshio Bando, Chunyi Zhi, Vikram Gadagkar, Prabal K. Maiti, D. V. S. Muthu, Dmitri Golberg, A. K. Sood
    Abstract:

    We have used Raman spectroscopy to study the behavior of multi-walled Boron Nitride nanotubes and hexagonal Boron Nitride crystals under high pressure. While Boron Nitride nanotubes show an irreversible transformation at about 12 GPa, hexagonal Boron Nitride exhibits a reversible phase transition at 13 GPa. We also present molecular dynamics simulations which suggest that the irreversibility of the pressure-induced transformation in Boron Nitride nanotubes is due to the polar nature of the bonds between Boron and nitrogen.

  • Comparative high pressure Raman study of Boron Nitride nanotubes and hexagonal Boron Nitride
    Chemical Physics Letters, 2006
    Co-Authors: Surajit Saha, Dimitri Golberg, Chengchun Tang, Yoshio Bando, Chunyi Zhi, D. V. S. Muthu, A. K. Sood
    Abstract:

    High pressure Raman experiments on Boron Nitride multi-walled nanotubes show that the intensity of the vibrational mode at ~ 1367 cm-1 vanishes at ~ 12 GPa and it does not recover under decompression. In comparison, the high pressure Raman experiments on hexagonal Boron Nitride show a clear signature of a phase transition from hexagonal to wurtzite at ~ 13 GPa which is reversible on decompression. These results are contrasted with the pressure behavior of carbon nanotubes and graphite.Comment: 13 pages and 5 figure