Misfit Dislocations
Misfit Dislocations - Related Videos
08:30
Intra-articular Shoulder Injection for Reduction Following Shoulder Dislocation
0 Views •
2023
Source: Rachel Liu, BAO, MBBCh, Emergency Medicine, Yale School of Medicine, New Haven, Connecticut, USA The anterior shoulder dislocation is one of the most common joint dislocations seen in emergency settings. In anterior shoulder dislocation, the humeral head is displaced out of the glenohumeral joint in front of the scapular glenoid, resulting in a loss of the articulation between the arm and the rest of the shoulder. This can be caused by a fall onto an abducted, extended, and externally...
06:57
Theoretical Calculation and Experimental Verification for Dislocation Reduction in Germanium Epitaxial Layers with Semicylindrical Voids on Silicon
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2020
Theoretical calculation and experimental verification are proposed for a reduction of threading dislocation (TD) density in germanium epitaxial layers with semicylindrical voids on silicon. Calculations based on the interaction of TDs and surface via image force, TD measurements, and transmission electron microscope observations of TDs are presented.
07:50
Electron Channeling Contrast Imaging for Rapid III-V Heteroepitaxial Characterization
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Cited by 22 •
2015
The use of electron channeling contrast imaging in a scanning electron microscope to characterize defects in III-V/Si heteroexpitaxial thin films is described. This method yields similar results to plan-view transmission electron microscopy, but in significantly less time due to lack of required sample preparation.
07:15
A Novel Method for In Situ Electromechanical Characterization of Nanoscale Specimens
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Cited by 2 •
2017
Isolating electrical and thermal effects on electrically assisted deformation (EAD) is very difficult using macroscopic samples. Metallic sample micro- and nanostructures together with a custom test procedure have been developed to evaluate the impact of applied current on the formation without joule heating and evolution of dislocations on these samples.
09:42
Analysis of Thermal Expansion via Dilatometry
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2023
Source: J. Jacob Chavez, Ryan T. Davis, and Taylor D. Sparks, Department of Materials Science and Engineering, The University of Utah, Salt Lake City, UT Thermal expansion is extremely important when considering which materials will be used in systems that experience fluctuations in temperature. A high or low thermal expansion in a material may or may not be desirable, depending on the application. For instance, in a common liquid thermometer, a material with a high thermal expansion would be...
FAQs
A growing film can initially accommodate the difference in lattice spacing by deforming elastically while maintaining alignment with its substrate. This accommodation is limited, however, because continued growth increases the resulting misfit strain. Once the film exceeds a critical thickness, forming interfacial dislocations provides another way to relieve that strain, changing the interface structure and its engineering consequences.
These characteristics determine how effectively the interface accommodates lattice mismatch and how the resulting stresses are distributed. Their influence extends beyond strain relief: they can affect residual stress, crystal quality, and the electrical or mechanical performance of the heterostructure. Consequently, engineers must consider not only whether dislocations form, but also their population, organization, and mobility.
Critical thickness marks the point at which elastic accommodation of lattice mismatch is no longer sufficient for the growing film. Below this point, the film remains aligned while deforming elastically; beyond it, interfacial dislocations can form and relieve misfit strain. This relationship makes film thickness an important design consideration when controlling interface stress and crystal quality.
The growth process can be evaluated as a sequence of interface states: initial elastic deformation, approach to a critical thickness, and possible formation of interfacial dislocations. After growth, their density, arrangement, and motion are relevant indicators because they connect the lattice mismatch to residual stress and material performance. This framework helps relate growth conditions to the resulting heterostructure.
Misfit dislocations matter wherever an engineered thin-film interface must maintain controlled structural and functional properties. The provided examples include semiconductor devices, optoelectronic materials, protective coatings, and other thin-film systems. In each case, interface dislocation behavior can influence crystal quality, residual stress, and electrical or mechanical performance, making it relevant to material selection and heterostructure design.
In semiconductor and optoelectronic heterostructures, the interface is part of the engineered material system rather than merely a boundary between layers. Misfit dislocations can alter crystal quality and electrical performance while also contributing to residual stress. Understanding their formation and characteristics therefore helps engineers evaluate how lattice mismatch may affect the functionality and reliability of these structures.