Atomic structures and stabilities of zigzag- and armchair-type boron nitride nanotubes studied by high-resolution electron microscopy and molecular mechanics calculation

2004 ◽  
Vol 13 (4-8) ◽  
pp. 1254-1260 ◽  
Author(s):  
Takeo Oku ◽  
Ichihito Narita
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Boron Nitride ◽  
Molecular Mechanics ◽  
High Resolution Electron Microscopy ◽  
Boron Nitride Nanotubes ◽  
Atomic Structures ◽  
Resolution Electron ◽  
Molecular Mechanics Calculation

Catalyst-Free Synthesis of Single-Wall Boron Nitride Nanotubes via Laser Ablation

2000 ◽  
Vol 633 ◽  
Author(s):  
Roland S. Lee ◽  
Julie Gavillet ◽  
Marc Lamy de la Chapelle ◽  
Jean-Lou Cochon ◽  
Daniel Pigache ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Laser Ablation ◽  
Chemical Composition ◽  
High Resolution ◽  
Boron Nitride ◽  
Energy Loss ◽  
High Resolution Electron Microscopy ◽  
Boron Nitride Nanotubes ◽  
Resolution Electron ◽  
Electron Energy Loss

AbstractBoron nitride nanotubes (BN-NTs) were synthesized in “mass” quantities (∼0.6 g/h) using a continuous CO2 laser ablation reactor described in the literature [1]. High-resolution electron microscopy (HRTEM) analyses have shown the nanotubes to be organized in “ropes” comprising ∼10 tubes. Analysis of HRTEM images indicate that the majority of the tubes are zig-zag. The chemical composition of the tubes was confirmed using electron energy loss spectroscopy (EELS) analysis, which also determined that nanoparticles terminating tube ends were composed of pure boron covered by BN fullerene-like “cages”. The growth mechanism of the nanotubes seems to be “root-based” with tubes growing from boron nanoparticles dispersed throughout the samples; the non-particle-terminated ends of the tubes exhibit flat “caps” characteristic of BN-NTs [2].

Interfacial Atomic Structures During Cobalt Silicidation

1990 ◽  
Vol 202 ◽  
Author(s):  
A. Catana ◽  
P.E. Schmid
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
High Resolution Electron Microscopy ◽  
Atomic Scale ◽  
Type B ◽  
Cross Sectional ◽  
Atomic Structures ◽  
Resolution Electron ◽  
Predominant Orientation ◽  
Lower Temperature

ABSTRACTHigh Resolution Electron Microscopy (HREM) and image calculations are combined to study microstructural changes related to the CoSi/Si-CoSi/CoSi2/Si-CoSi2/Si transformations. The samples are prepared by UHV e-beam evaporation of Co layers (2 nm) followed by annealing at 300°C or 400°C. Cross-sectional observations at an atomic scale show that the silicidation of Co at the lower temperature yields epitaxial CoSi/Si domains such that [111]Si // [111]CoSi and <110>Si // <112>CoSi. At about 400°C CoSi2 nucleates at the CoSi/Si interface. During the early stages of this chemical reaction, an epitaxial CoSi/CoSi2/Si system is observed. The predominant orientation is such that (021) CoSi planes are parallel to (220) CoSi2 planes, the CoSi2/Si interface being of type B. The growth of CoSi2 is shown to proceed at the expense of both CoSi and Si.

Morphology of Nanometric Boron Nitride Powders Produced by Laser Pyrolysis

1994 ◽  
Vol 359 ◽  
Author(s):  
F. Willaime ◽  
L. Boulanger ◽  
M. Cauchetier
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
High Resolution ◽  
Boron Nitride ◽  
Carbon Materials ◽  
High Resolution Electron Microscopy ◽  
Nitrogen Atmosphere ◽  
Major Constituent ◽  
Structure And Morphology ◽  
Resolution Electron

ABSTRACTUltrafine boron nitride powders were synthesized by laser driven reactions in BC13-NH3 mixtures. The structure and morphology of the graphitic nanoparticles generated in this process were investigated by high-resolution electron microscopy. Polyhedral concentric shells (ranging in size from 30 nm to more than 100 nm) are a major constituent of the as-pyrolyzed powder. This onion-like configuration is very similar to that observed in carbon materials. After heat treatment at 1650°C under nitrogen atmosphere, plate-like particles with a few perfectly flat graphitic sheets (10 to 50 layer thick, 50 nm in diameter) are formed.

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