Characterization of the Structure and Polarity of Twin Boundaries in GaP

1998 ◽  
Vol 510 ◽  
Author(s):  
Dov Cohent ◽  
D.L. Medlin ◽  
C. Barry Carter
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Twin Boundary ◽  
Atomic Structure ◽  
Twin Boundaries ◽  
Planar Defects ◽  
Transmission Electron ◽  
Crystallographic Planes

AbstractThe structure of planar defects in GaP films grown by MBE on Si (110) was investigated by transmission electron microscopy. Growth of GaP films on the (110) surface produced numerous microtwins which formed both first and second order twin boundaries. Using high-resolution transmission electron microscopy, the atomic structure of Σ=3 and Σ=9 twin boundaries were studied. Both the Σ=3 and Σ=9 interfaces were observed to facet along specific crystallographic planes. Geometric models of the Σ=9 {221} twin boundary accounting for different polar bonding configurations were proposed and compared with experimental observations.

Atomic Scale Analysis of Planar Defects in Polycrystalline Diamond

2006 ◽  
Vol 12 (6) ◽  
pp. 492-497 ◽  
Author(s):  
Rolf Erni ◽  
Bert Freitag ◽  
Peter Hartel ◽  
Heiko Müller ◽  
Peter Tiemeijer ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Polycrystalline Diamond ◽  
Atomic Scale ◽  
Twin Boundaries ◽  
Axis Orientation ◽  
Planar Defects ◽  
Transmission Electron ◽  
Local Distortions

Planar defects in a polycrystalline diamond film were studied by high-resolution transmission electron microscopy (HRTEM) and high-resolution scanning transmission electron microscopy (STEM). In both modes, sub-Ångström resolution was achieved by making use of two aberration-corrected systems; a TEM and a STEM CS-corrected microscope, each operated at 300 kV. For the first time, diamond in 〈110〉 zone-axis orientation was imaged in STEM mode at a resolution that allows for resolving the atomic dumbbells of carbon at a projected interatomic distance of 89 pm. Twin boundaries that show approximately the Σ3 CSL structure reveal at sub-Ångström resolution imperfections; that is, local distortions, which break the symmetry of the ideal Σ3 type twin boundary, are likely present. In addition to these imperfect twin boundaries, voids on the atomic level were observed. It is proposed that both local distortions and small voids enhance the mechanical toughness of the film by locally increasing the critical stress intensity factor.

scholarly journals Synthesize and Characterization of Hollow Boron-Nitride Nanocages

2009 ◽  
Vol 2009 ◽  
pp. 1-4 ◽  
Author(s):  
W. S. Zhang ◽  
J. G. Zheng ◽  
W. F. Li ◽  
D. Y. Geng ◽  
Z. D. Zhang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Boron Nitride ◽  
Growth Mechanism ◽  
Spherical Shape ◽  
Amorphous Boron ◽  
Transmission Electron ◽  
Ammonia Atmosphere

The boron-nitride (BN) nanocages are synthesized by nitrogenation of amorphous boron nanoparticles at 1073 K under nitrogen and ammonia atmosphere. The BN nanocages exhibit a well-crystallized feature with nearly pentagonal or spherical shape, depending on their size. High-resolution transmission electron microscopy studies reveal that they are hollow nanocages. The growth mechanism of the BN nanocages is proposed.

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