The Importance of Threading Dislocations on the Motion of Domain Boundaries in Thin Films

Science ◽  
2005 ◽  
Vol 308 (5726) ◽  
pp. 1303-1305 ◽  
Author(s):  
F. E. Gabaly
Keyword(s):  
Thin Films ◽  
Threading Dislocations ◽  
Domain Boundaries

Effect of domain boundaries on the electrical properties of crystalline Gd2O3 thin films

2008 ◽  
Vol 93 (18) ◽  
pp. 182907 ◽  
Author(s):  
Apurba Laha ◽  
E. Bugiel ◽  
J. X. Wang ◽  
Q. Q. Sun ◽  
A. Fissel ◽  
...  
Keyword(s):  
Thin Films ◽  
Electrical Properties ◽  
Domain Boundaries

Microstructral Investigations on GaN Films Grown by Laser Induced Molecular Beam Epitaxy

1999 ◽  
Vol 595 ◽  
Author(s):  
H. Zhou ◽  
F. Phillipp ◽  
M. Gross ◽  
H. Schröder
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Threading Dislocations ◽  
Planar Defects ◽  
Sapphire Substrates ◽  
Inversion Domain ◽  
Transmission Electron ◽  
Domain Boundaries ◽  
Line Defects ◽  
Inversion Domain Boundaries

AbstractMicrostructural investigations on GaN films grown on SiC and sapphire substrates by laser induced molecular beam epitaxy have been performed. Threading dislocations with Burgers vectors of 1/3<1120>, 1/3<1123> and [0001] are typical line defects, predominantly the first type of dislocations. Their densities are typically 1.5×1010 cm−2 and 4×109 cm−2 on SiC and sapphire, respectively. Additionally, planar defects characterized as inversion domain boundaries lying on {1100} planes have been observed in GaN/sapphire samples with an inversion domain density of 4×109 cm−2. The inversion domains are of Ga-polarity with respect to the N-polarity of the adjacent matrix. However, GaN layers grown on SiC show Ga-polarity. Possible reasons for the different morphologies and structures of the films grown on different substrates are discussed. Based on an analysis of displacement fringes of inversion domains, an atomic model of the IDB-II with Ga-N bonds across the boundary was deduced. High resolution transmission electron microscopy (HRTEM) observations and the corresponding simulations confirmed the IDB-II structure determined by the analysis of displacement fringes.

Strain Relaxation in Thin Films: the Effect of Dislocation Blocking

1999 ◽  
Vol 594 ◽  
Author(s):  
Peter J Goodhew
Keyword(s):  
Thin Films ◽  
Experimental Evidence ◽  
Strain Relaxation ◽  
Dislocation Line ◽  
Small Strain ◽  
Threading Dislocations ◽  
Semiconductor Films ◽  
Strained Layers ◽  
Dislocation Configuration ◽  
Perpendicular Line

AbstractThe relaxation of strained layers frequently occurs by the glide of threading dislocations. From very early on in the relaxation process, gliding dislocations will be forced to intersect a number of prior dislocations with almost-perpendicular line directions and their progress may be blocked. This effect has been widely reported in semiconductor films, and there is some experimental evidence that it is reduced when layers are grown on vicinal substrates. This implies that the blocking is sensitively dependent on the dislocation configuration and in particular on the dislocation line directions.In this paper the interactions between gliding threading dislocations and the perpendicular or nearly-perpendicular dislocation in their path are modelled quantitatively. The differences arising from different initial dislocation configurations and different predominant line directions are found to be small. Strain relaxation, at least in its early stages, should be virtually independent of the initial dislocation configuration.

Microstructure and optical loss in epitaxial (Pb, La)TiO3 thin films on (001) MgO

1998 ◽  
Vol 13 (4) ◽  
pp. 995-1001 ◽  
Author(s):  
Young Min Kang ◽  
Sunggi Baik
Keyword(s):  
Thin Films ◽  
Smooth Surface ◽  
Optical Loss ◽  
Optical Losses ◽  
Coupling Technique ◽  
Optical Propagation ◽  
Domain Boundaries ◽  
Propagation Losses ◽  
La Substitution ◽  
Surface Morphologies

Surface morphologies and microstructures of epitaxial (Pb1−xLax)TiO3 (PLT, x = 0.00, 0.08, 0.16, and 0.24) thin films grown on (001) MgO have been investigated using SEM, AFM, and TEM. Surface roughness of PLT films varies severely with La concentration. For 0.08La-PLT film, very smooth surface has been achieved with 9.3 Å of RMS roughness. 0.00La- and 0.08La-PLT films show 90° domain structure, and periodic dimension of the domain is reduced by La substitution. 0.16La- and 0.24La-PLT films show the presence of triangular grains, causing rough surface and poor crystal quality. However, they are distributed uniformly in 0.16La-PLT film while agglomerated in 0.24La-PLT film. Optical propagation losses of PLT films measured by prism coupling technique were 22.3, 6.0, 11.4, and 20.7 dB/cm for x = 0.00, 0.08, 0.16, and 0.24, respectively. Such a variation in optical losses seemed to be due to the surface morphology and abundance of domain boundaries that change continuously as a function of La concentration in epitaxial PLT thin films.

scholarly journals Structural Property Study for GeSn Thin Films

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3645
Author(s):  
Liyao Zhang ◽  
Yuxin Song ◽  
Nils von den Driesch ◽  
Zhenpu Zhang ◽  
Dan Buca ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Molecular Beam ◽  
Chemical Vapor ◽  
Threading Dislocations ◽  
X Ray Diffraction ◽  
Cross Sectional ◽  
X Ray ◽  
Transmission Electron

The structural properties of GeSn thin films with different Sn concentrations and thicknesses grown on Ge (001) by molecular beam epitaxy (MBE) and on Ge-buffered Si (001) wafers by chemical vapor deposition (CVD) were analyzed through high resolution X-ray diffraction and cross-sectional transmission electron microscopy. Two-dimensional reciprocal space maps around the asymmetric (224) reflection were collected by X-ray diffraction for both the whole structures and the GeSn epilayers. The broadenings of the features of the GeSn epilayers with different relaxations in the ω direction, along the ω-2θ direction and parallel to the surface were investigated. The dislocations were identified by transmission electron microscopy. Threading dislocations were found in MBE grown GeSn layers, but not in the CVD grown ones. The point defects and dislocations were two possible reasons for the poor optical properties in the GeSn alloys grown by MBE.

scholarly journals Atomic structure of threading dislocations in AlN thin films

2009 ◽  
Vol 404 (23-24) ◽  
pp. 4886-4888 ◽  
Author(s):  
Yuki Tokumoto ◽  
Naoya Shibata ◽  
Teruyasu Mizoguhci ◽  
Takahisa Yamamoto ◽  
Yuichi Ikuhara
Keyword(s):  
Thin Films ◽  
Atomic Structure ◽  
Threading Dislocations

Thickness dependence of ferroelectric domains in thin ferroelectric crystals

1994 ◽  
Vol 52 ◽  
pp. 562-563
Author(s):  
F. Tsai ◽  
J. M. Cowley
Keyword(s):  
Thin Films ◽  
Bulk Material ◽  
Ferroelectric Properties ◽  
Bulk Materials ◽  
Free Standing ◽  
Ferroelectric Crystals ◽  
Transmission Electron ◽  
Ferroelectric Domains ◽  
Domain Boundaries ◽  
Long Time

Transmission electron microscopy (TEM) has been used to study the microstructures, especially the ferroelectric domains and boundaries, of ferroelectric crystals and free-standing thin films because they are closely related to the ferroelectric properties of thin films. But, for a long time observations have been made on the assumption that the properties of ferroelectric domains and domain boundaries are the same as those of the bulk crystal, even though sometimes some evidence may have been shown that ferroelectric domains in thin films could be different from those in the bulk material. In fact, weak ferroelectricity of thin films has been noticed. It was found that the ferroelectric characteristics of thin BaTiO3 ferroelectric films deposited on substrates are different from those of bulk materials. Although in their analysis interfaces and grain boundaries are involved, the mechanism of weak ferroelectricity of thin films and the microstructures which are related to the ferroelectricity of the film remains unclear.

Pinning of 90° domain boundaries at interface dislocations in BaTiO3/LaAIO3 {100}

1996 ◽  
Vol 54 ◽  
pp. 124-125
Author(s):  
Z.-R. Dai ◽  
Z.L. Wang ◽  
X.F. Duan ◽  
J. Zhang
Keyword(s):  
Thin Films ◽  
Chemical Vapor ◽  
Organic Chemical ◽  
Epitaxial Thin Films ◽  
Transmission Electron ◽  
Domain Boundaries ◽  
Potential Applications ◽  
Metal Organic ◽  
Organic Chemical Vapor Deposition

Epitaxially grown BaTiO3 thin films have potential applications in microelectronics and integrated photonics. The ferroelectric property of this material is largely determined by the domain structure. It is believed that the structure of the substrate would have profound effect on the quality of BaTiO3 epitaxial thin films. This paper reports our studies on the pinning of 90° domain boundaries at interface dislocations.Epitaxial BaTiO3 thin films were deposited on single crystalline LaAIO3 (100) substrates at 800°C by metal-organic chemical vapor deposition (MOCVD). Cross-section specimens of the films were studied at 200 kV using an JEOL 2010 high-resolution transmission electron microscope (HRTEM).

scholarly journals Effect of screw threading dislocations and inverse domain boundaries in GaN on the shape of reciprocal-space maps

2017 ◽  
Vol 50 (2) ◽  
pp. 555-560 ◽  
Author(s):  
Mykhailo Barchuk ◽  
Mykhaylo Motylenko ◽  
Gleb Lukin ◽  
Olf Pätzold ◽  
David Rafaja
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Reciprocal Space ◽  
Threading Dislocations ◽  
X Ray Diffraction ◽  
Reciprocal Space Mapping ◽  
Vapour Phase Epitaxy ◽  
X Ray ◽  
Transmission Electron ◽  
Domain Boundaries

The microstructure of polar GaN layers, grown by upgraded high-temperature vapour phase epitaxy on [001]-oriented sapphire substrates, was studied by means of high-resolution X-ray diffraction and transmission electron microscopy. Systematic differences between reciprocal-space maps measured by X-ray diffraction and those which were simulated for different densities of threading dislocations revealed that threading dislocations are not the only microstructure defect in these GaN layers. Conventional dark-field transmission electron microscopy and convergent-beam electron diffraction detected vertical inversion domains as an additional microstructure feature. On a series of polar GaN layers with different proportions of threading dislocations and inversion domain boundaries, this contribution illustrates the capability and limitations of coplanar reciprocal-space mapping by X-ray diffraction to distinguish between these microstructure features.

Sign in / Sign up

Export Citation Format

Share Document