Thermally activated polarization dynamics under the effects of lattice mismatch strain and external stress in ferroelectric film

2012 ◽  
Vol 112 (1) ◽  
pp. 014112 ◽  
Author(s):  
Y. Zhang ◽  
X. L. Zhong ◽  
M. Vopson ◽  
J. B. Wang ◽  
Y. C. Zhou
Keyword(s):  
Lattice Mismatch ◽  
External Stress ◽  
Ferroelectric Film ◽  
Mismatch Strain ◽  
Thermally Activated ◽  
Lattice Mismatch Strain

Surface-growth-mode-induced strain effects on the metal–insulator transition in epitaxial vanadium dioxide thin films

RSC Advances ◽  
2015 ◽  
Vol 5 (98) ◽  
pp. 80122-80128 ◽  
Author(s):  
Mengmeng Yang ◽  
Yuanjun Yang ◽  
Bin Hong ◽  
Liangxin Wang ◽  
Zhenlin Luo ◽  
...  
Keyword(s):  
Vanadium Dioxide ◽  
Lattice Mismatch ◽  
Compressive Strain ◽  
Epitaxial Films ◽  
Surface Growth ◽  
Growth Mode ◽  
Metal Insulator ◽  
Mismatch Strain ◽  
Lattice Mismatch Strain ◽  
Vanadium Dioxide Thin Films

The surface growth mode can induce the anomalous compressive strain in thicker VO2/Al2O3 epitaxial films, which can't be explained by conventional epitaxial lattice-mismatch. Strain may be an effective tool for manipulating MIT of the VO2 films.

Effect of Lattice Mismatch Strain Grading on the Electromechanical Behavior of Functionally Graded Quantum Dots

2018 ◽  
Vol 759 ◽  
pp. 71-75 ◽  
Author(s):  
Peter L. Bishay ◽  
Bhavin Sampat ◽  
Jan Sladek ◽  
Ernian Pan ◽  
Vladimir Sladek
Keyword(s):  
Material Properties ◽  
Lattice Mismatch ◽  
Growth Direction ◽  
Functionally Graded ◽  
Tuning Parameter ◽  
Mismatch Strain ◽  
Electromechanical Behavior ◽  
Mechanical Models ◽  
Lattice Mismatch Strain ◽  
Fully Coupled

A fully coupled thermo-electro-mechanical models of cylindrical and truncated conical GaN/AlN Functionally Graded Quantum Dot (FGQD) systems with and without WL are analyzed in this study to determine the effect of lattice mismatch strain grading on the electromechanical behavior of the FGQD system. This has a technological and fundamental importance because the production methodology adopted for manufacturing QDs enables the composition of the QD material to be graded in the growth direction, so the material properties as well as the induced mismatch strain between the QD and the carrier matrix are accordingly graded. The power law is used to describe the grading function. Based on the obtained results, grading of material properties and lattice mismatch strain have significant effect on the distribution of the electromechanical quantities inside the QD and can be used as another tuning parameter in the design of QD systems.

Effects of Surface Constraints on Stresses in Heteroepitaxial Films Grown on Compliant Substrates

2001 ◽  
Vol 695 ◽  
Author(s):  
Zhaohua Feng ◽  
Edward G. Lovell ◽  
Roxann L. Engelstad ◽  
Thomas F. Kuech
Keyword(s):  
Lattice Mismatch ◽  
Defect Production ◽  
Factors Affecting ◽  
Mismatch Strain ◽  
Compliant Substrates ◽  
Different Types ◽  
Lattice Mismatch Strain ◽  
And Control ◽  
Surface Constraints ◽  
Stress Variations

ABSTRACTAs films heteroepitaxially grow on substrates, lattice mismatch strain at the interfaces causes stresses in the films and substrates. These stresses can have deleterious effects on film quality. To facilitate an understanding of defect production and control during growth of films on compliant substrates, transient finite element models were developed to simulate the complete mechanical stress and strain fields. Effects of constraints between the template and handle wafer on the film stresses were examined. The investigation showed that different types of constraints caused stress variations over a large range. Other factors affecting the stresses, such as lattice mismatch strain, wafer radius, film and template thickness, were also assessed.

Lattice-mismatch-strain induced inhomogeneities in epitaxial La0.7Ca0.3MnO3 films

2007 ◽  
Vol 90 (1) ◽  
pp. 012509 ◽  
Author(s):  
Guanyin Gao ◽  
Shaowei Jin ◽  
Wenbin Wu
Keyword(s):  
Lattice Mismatch ◽  
Mismatch Strain ◽  
Lattice Mismatch Strain

Stress Generation and Relaxation during Film Heteroepitaxy on a Compliant Substrate with a Viscoelastic Glass Interlayer

2001 ◽  
Vol 696 ◽  
Author(s):  
Zhaohua Feng ◽  
Edward G. Lovell ◽  
Roxann L. Engelstad ◽  
Peter D. Moran ◽  
Thomas F. Kuech
Keyword(s):  
Film Growth ◽  
Lattice Mismatch ◽  
Three Dimensional ◽  
Stress Generation ◽  
Compliant Substrate ◽  
Factors Affecting ◽  
Mismatch Strain ◽  
Compliant Substrates ◽  
Film Substrate ◽  
Lattice Mismatch Strain

AbstractLattice mismatch strain between films and substrates causes stresses in each and degrades the film quality. Compliant substrates can decrease the stresses and dislocation density in the film. A particular type of compliant substrate, which consists of a thin template, a handle wafer and a glass interlayer, is discussed here. Three-dimensional axisymmetric finite element models were developed to simulate the film-substrate structure and analyze stress generation and relaxation. The materials of film and template were considered as elastic but the glass interlayer was viscoelastic at the film growth temperature. Factors affecting stress generation and relaxation are reported.

Growth and Characterization of Epitaxial NiMnSb/PtMnSb C1b Heusler alloy superlattices

1999 ◽  
Vol 14 (4) ◽  
pp. 1560-1569 ◽  
Author(s):  
F. B. Mancoff ◽  
J. F. Bobo ◽  
O. E. Richter ◽  
K. Bessho ◽  
P. R. Johnson ◽  
...  
Keyword(s):  
Heusler Alloy ◽  
Lattice Mismatch ◽  
X Ray Diffraction ◽  
Cross Sectional ◽  
Perpendicular Magnetization ◽  
Mismatch Strain ◽  
Transmission Electron ◽  
Strain Energy Minimization ◽  
Sputter Deposited ◽  
Lattice Mismatch Strain

We have sputter deposited NiMnSb/PtMnSb Heusler alloy superlattices with bilayer periods from 9–160 Å. X-ray diffraction and cross-sectional transmission electron microscopy (TEM) measurements indicate that even for short bilayer periods, the superlattices are compositionally modulated, epitaxial, and maintain the Heusler alloy C1b structure. Low- and high-angle diffraction profiles are in agreement with simulations of the superlattice peaks. TEM images reveal defects, including stacking faults, which help relieve lattice mismatch strain. Energy minimization calculations of the stacking fault density are within a factor of 3 of the density observed by TEM. The saturation magnetization of the superlattices is close to bulk PtMnSb and NiMnSb, with a tendency for perpendicular magnetization at short bilayer periods.

Stacking Faults around the Hetero-Interface Induced by 6H-SiC Polytype Transformation on 3C-SiC with Solution Growth

2010 ◽  
Vol 645-648 ◽  
pp. 363-366 ◽  
Author(s):  
Kazuaki Seki ◽  
Kai Morimoto ◽  
Toru Ujihara ◽  
Tomoharu Tokunaga ◽  
Katsuhiro Sasaki ◽  
...  
Keyword(s):  
Strain Energy ◽  
Grown Crystal ◽  
Lattice Mismatch ◽  
Stacking Faults ◽  
Stacking Fault ◽  
The Other ◽  
Solution Growth ◽  
Mismatch Strain ◽  
Polytype Transformation ◽  
Lattice Mismatch Strain

6H-SiC hetero-epitaxially grown on a (111) 3C-SiC was observed with TEM. High-density stacking faults were formed around the hetero-interface, and the density of stacking faults decreased with increasing distance from interface. On the other hand, when 3C-SiC was homo-epitaxially grown on a 3C-SiC, any stacking faults did not exist at the interface between the grown crystal and the seed crystal. Thus, the stacking faults formation started from the 6H/3C hetero-interface. Considering the lattice-mismatch strain between 3C-SiC and 6H-SiC, the strain energy is equivalent to the stacking fault energy of 6H-SiC. This similarity suggests that the stacking faults formation could be caused by the relaxation of the lattice-mismatch strain.

Defects, Dislocations and Degradation of Compound Semiconductors

1982 ◽  
Vol 14 ◽  
Author(s):  
W. Dexter Johnston
Keyword(s):  
Lattice Mismatch ◽  
Electrical Power ◽  
Mechanical Damage ◽  
Alloy System ◽  
Dark Line ◽  
Extended Defect ◽  
Mismatch Strain ◽  
Device Processing ◽  
Line Defects ◽  
Lattice Mismatch Strain

ABSTRACTDiode lasers and/or LEDs fabricated from the Ga1 − xAlxAs/GaAs or In1 −xGaxAsyP1−y alloy system provide the basis for rapidly developing optical communications systems. These devices are operated at very high optical and electrical power densities, and the inevitable less-than-perfect efficiency results in intense local thermal and athermal lattice excitation. This in turn can lead to generation, motion and growth of extended defect structures including dislocation networks, precipitation of impurities, or phase separation.For the AlxGa1−xAs material, a predominant degradation effect is the development of so-called <100> “dark line defects” (DLDs). These have been shown to arise from recombination enhanced climb of threading dislocations giving rise to dipole loops of a primarily interstitial character. A less common form, the <110> DLDs, is associated with slip and typically arises from the strain associated with mechanical damage or careless handling or device processing.The In1−xGaxAsyP 1−y device material affords less energy per recombina ion event by virtue of its smaller band-gaps, but is likely to have more lattice mismatch strain than Ga1−xAlxAs for typical compositions of device interest. Thus slip, <110> DLDs, and precipitates are the commonly observed features of In1−xGaxAsyP1−y degradation.

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