Mixed partial dislocation core structure in GaN by high resolution electron microscopy

2006 ◽  
Vol 203 (9) ◽  
pp. 2156-2160 ◽  
Author(s):  
J. Kioseoglou ◽  
G. P. Dimitrakopulos ◽  
Ph. Komninou ◽  
Th. Kehagias ◽  
Th. Karakostas
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Partial Dislocation ◽  
Dislocation Core ◽  
High Resolution Electron Microscopy ◽  
Core Structure ◽  
Resolution Electron ◽  
Dislocation Core Structure

Nanoscale Measurement of Stress and Strain by Quantitative High-Resolution Electron Microscopy

2005 ◽  
Vol 482 ◽  
pp. 39-44 ◽  
Author(s):  
Martin J. Hÿtch ◽  
Jean-Luc Putaux ◽  
Jean-Michel Pénisson
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Spatial Resolution ◽  
Strain Tensor ◽  
Dislocation Core ◽  
High Resolution Electron Microscopy ◽  
Stress And Strain ◽  
Fourier Space ◽  
Resolution Electron ◽  
Anisotropic Elastic

The geometric phase technique (GPA) for measuring the distortion of crystalline lattices from high-resolution electron microscopy (HRTEM) images will be described. The method is based on the calculation of the “local” Fourier components of the HRTEM image by filtering in Fourier space. The method will be illustrated with a study of an edge dislocation in silicon where displacements have been measured to an accuracy of 3 pm at nanometre resolution as compared with anisotropic elastic theory calculations. The different components of the strain tensor will be mapped out in the vicinity of the dislocation core and compared with theory. The accuracy is of the order of 0.5% for strain and 0.1° for rigid-body rotations. Using bulk elastic constants for silicon, the stress field is determined to 0.5 GPa at nanometre spatial resolution. Accuracy and the spatial resolution of the technique will be discussed.

Dislocation core studies using high resolution electron microscopy

1978 ◽  
Vol 36 (1) ◽  
pp. 182-183
Author(s):  
D.J.H. Cockayne ◽  
G.R. Anstis
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Unique Solution ◽  
Lattice Distortion ◽  
Image Interpretation ◽  
Dislocation Core ◽  
High Resolution Electron Microscopy ◽  
Resolution Electron ◽  
Image Position ◽  
Image Detail

The interpretation of high resolution (0.5nm) image detail to study dislocation cores relies upon image calculations for its justification. The scattering equations used to calculate these images make use of various approximations, and their validity at this level of resolution has been in doubt. Because of this, a detailed study has been made of the various methods of image calculation, and the reliability of image interpretation for a number of experimental situations has been determined.Images of dislocations of arbitrary resolution can be calculated by an extension of the approach considered by Howie and Basinski. Given an expansion of the potential V(r) = Σgvg(r) exp (2Πig.r) and wavefunctionsthen, for a given incident wavefunction, the wavefunction ψ(r) = Σgϕg(r) exp (2Πig.r) is the unique solution to the form of Schroedinger's equation in which backscattering is neglected, irrespective of the extent of lattice distortion.

Structural Studies of Metal-Semiconductor Interfaces with High-Resolution Electron Microscopy

1982 ◽  
Vol 14 ◽  
Author(s):  
J. M. Gibson ◽  
R. T. Tung ◽  
J. M. Poate
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Dislocation Core ◽  
High Resolution Electron Microscopy ◽  
Nucleation And Growth ◽  
Interfacial Structure ◽  
Preparation Conditions ◽  
Semiconductor Interfaces ◽  
Resolution Electron ◽  
Crystal Films

ABSTRACTWe have studied interface atomic structure in epitaxial cobalt and nickel disilicides on silicon using high-resolution transmission electron microscopy. By employing UHV techniques during deposition and reaction we have grown truly single-crystalline NiSi2 and CoSi2 films on (111) Si and in the former case on (100) Si. These films are shown to be continuous to below 10Å thickness. By close control over preparation conditions, afforded by UHV, we can greatly influence the nucleation and growth of these films to the extent, for example with NiSi2 on (111)Si, of yielding continuous single-crystal films with either of two orientations as desired. Whilst in the (111) NiSi2 on Si system the interfacial structure invariably appears to well-fit a model in which metal atoms nearest to the interface are 7-fold co-ordinated, for (111) CoSi2 on Si agreement is generally better with a model involving 5-fold co-ordination of these atoms. A misfit dislocation core is also imaged. Results are discussed in the light of silicide nucleation and growth. The structure and stability of the (100) NiSi2 on Si interface is also considered.

Examination of Dislocation Cores in Ni3Al Using High Resolution Electron Microscopy

1988 ◽  
Vol 133 ◽  
Author(s):  
Martin A. Crimp ◽  
P. M. Hazzledine
Keyword(s):  
Electron Microscopy ◽  
Computer Simulation ◽  
High Resolution ◽  
Yield Strength ◽  
Deformation Temperature ◽  
Dislocation Core ◽  
High Resolution Electron Microscopy ◽  
The Core ◽  
Resolution Electron ◽  
Theoretical Predictions

ABSTRACTHigh resolution electron microscopy has been used to study the core structure of a/2[101] and a/3<112> dislocations in Ni3Al deformed in the range of increasing strength with temperature. a/3<112> coupled SISFs were found to lie on (111) and their structure agreed well with theoretical predictions. a/2[101] superpartials were always dissociated on (111) or (111) planes while the APB plane was found to be (010). Computer simulation of dislocation core structures were found to agree well with the observed dissociations. The APB width was found to increase significantly with increasing deformation temperature near the peak yield strength temperature.

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