scholarly journals High-resolution x-ray diffraction from multilayered self-assembled Ge dots

1997 ◽  
Vol 55 (23) ◽  
pp. 15652-15663 ◽  
Author(s):  
A. A. Darhuber ◽  
P. Schittenhelm ◽  
V. Holý ◽  
J. Stangl ◽  
G. Bauer ◽  
...  
Keyword(s):  
High Resolution ◽  
X Ray Diffraction ◽  
X Ray ◽  
Self Assembled

Structural Investigations of Self-Assembled Ge-Dots by X-Ray Diffraction and Reflection

1996 ◽  
Vol 448 ◽  
Author(s):  
A.A. Darhuber ◽  
V. Holy ◽  
J. Stangl ◽  
G. Bauer ◽  
P. Schittenhelm ◽  
...  
Keyword(s):  
High Resolution ◽  
X Ray Diffraction ◽  
Structural Investigations ◽  
X Ray ◽  
Si Substrates ◽  
Self Organized ◽  
Lateral Ordering ◽  
Self Assembled ◽  
Square Array ◽  
Vertical Correlation

AbstractSelf-organized Ge-dots on (001)-oriented Si-substrates have been studied using two-dimensionally resolved high resolution x-ray diffraction and reflectivity. The degree of the vertical correlation of the dot positions ("stacking") has been derived as well as a lateral ordering of the dots in a (disordered) square array with main axes parallel to ]100] and ]010].

Lateral and vertical ordering of self-assembled PbSe quantum dots studied by high-resolution X-ray diffraction

2000 ◽  
Vol 283 (1-3) ◽  
pp. 65-68 ◽  
Author(s):  
V. Holý ◽  
J. Stangl ◽  
G. Springholz ◽  
M. Pinczolits ◽  
G. Bauer ◽  
...  
Keyword(s):  
Quantum Dots ◽  
High Resolution ◽  
X Ray Diffraction ◽  
X Ray ◽  
Self Assembled

Effects of Rapid Thermal Annealing on the Intersubband Energy Spacing of Self-Assembled InAs/Gaas Quantum Dots

1999 ◽  
Vol 588 ◽  
Author(s):  
X. C. Wang ◽  
S. J. Chua ◽  
S. J. Xu ◽  
Z. H. Zhang
Keyword(s):  
Quantum Dots ◽  
Excited State ◽  
High Resolution ◽  
Thermal Treatment ◽  
Ground State ◽  
Infrared Detectors ◽  
Blue Shift ◽  
X Ray Diffraction ◽  
X Ray ◽  
Self Assembled

AbstractIn this paper, we showed the significant reduction of the energy spacing between ground state and excited state emissions from InAs/GaAs quantum dots due to interface interdiffusion induced by thermal treatment. In addition, the strong narrowing of the luminescence linewidth of the ground state and excited state emissions from the InAs dot layers for the annealed samples indicates an improvement of the size-distribution of the QDs. Large blue-shift of the energy positions of both emissions was also observed. High resolution X-Ray diffraction experiments give strong evidence of the interface atom interdiffusion in the annealed samples. This work shows ability to tune the wavelength for applications like infrared detectors and lasers based on intrasubband transitions of self-assembled QDs.

Structural Study of the Annealing of Alkylsiloxane Self-Assembled Monolayers on Silicon by High-Resolution X-ray Diffraction

1995 ◽  
Vol 99 (38) ◽  
pp. 14039-14051 ◽  
Author(s):  
M. A. Murphy ◽  
C. E. Nordgren ◽  
R. F. Fischetti ◽  
J. K. Blasie ◽  
L. J. Peticolas ◽  
...  
Keyword(s):  
High Resolution ◽  
Structural Study ◽  
Self Assembled Monolayers ◽  
X Ray Diffraction ◽  
X Ray ◽  
Assembled Monolayers ◽  
Self Assembled

A High Resolution Study of G.P. Zones in Aluminum - 4.2 at % Silver

1982 ◽  
Vol 40 ◽  
pp. 722-723 ◽  
Author(s):  
R. Gronsky
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Computer Simulations ◽  
Structural Characteristics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Resolution Study

The phenomenon of clustering in Al-Ag alloys has been extensively studied since the early work of Guinierl, wherein the pre-precipitation state was characterized as an assembly of spherical, ordered, silver-rich G.P. zones. Subsequent x-ray and TEM investigations yielded results in general agreement with this model. However, serious discrepancies were later revealed by the detailed x-ray diffraction - based computer simulations of Gragg and Cohen, i.e., the silver-rich clusters were instead octahedral in shape and fully disordered, atleast below 170°C. The object of the present investigation is to examine directly the structural characteristics of G.P. zones in Al-Ag by high resolution transmission electron microscopy.

Tubulin structure at intermediate resolution

1995 ◽  
Vol 53 ◽  
pp. 852-853
Author(s):  
K. H. Downing ◽  
S. G. Wolf ◽  
E. Nogales
Keyword(s):  
High Resolution ◽  
Structural Data ◽  
Therapeutic Drug ◽  
Zinc Ions ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
X Ray ◽  
Negative Stain ◽  
Functional Mechanisms ◽  
Tubulin Structure

Microtubules are involved in a host of critical cell activities, many of which involve transport of organelles through the cell. Different sets of microtubules appear to form during the cell cycle for different functions. Knowledge of the structure of tubulin will be necessary in order to understand the various functional mechanisms of microtubule assemble, disassembly, and interaction with other molecules, but tubulin has so far resisted crystallization for x-ray diffraction studies. Fortuitously, in the presence of zinc ions, tubulin also forms two-dimensional, crystalline sheets that are ideally suited for study by electron microscopy. We have refined procedures for forming the sheets and preparing them for EM, and have been able to obtain high-resolution structural data that sheds light on the formation and stabilization of microtubules, and even the interaction with a therapeutic drug.Tubulin sheets had been extensively studied in negative stain, demonstrating that the same protofilament structure was formed in the sheets and microtubules. For high resolution studies, we have found that the sheets embedded in either glucose or tannin diffract to around 3 Å.

scholarly journals Dislocation Arrangement in a Thick LEO GaN Film on Sapphire

2000 ◽  
Vol 5 (S1) ◽  
pp. 97-103
Author(s):  
Kathleen A. Dunn ◽  
Susan E. Babcock ◽  
Donald S. Stone ◽  
Richard J. Matyi ◽  
Ling Zhang ◽  
...  
Keyword(s):  
High Resolution ◽  
Electron Diffraction ◽  
Threading Dislocations ◽  
X Ray Diffraction ◽  
Burgers Vector ◽  
X Ray ◽  
The Third ◽  
Dislocation Arrangement ◽  
Image Position ◽  
Gan Film

Diffraction-contrast TEM, focused probe electron diffraction, and high-resolution X-ray diffraction were used to characterize the dislocation arrangements in a 16µm thick coalesced GaN film grown by MOVPE LEO. As is commonly observed, the threading dislocations that are duplicated from the template above the window bend toward (0001). At the coalescence plane they bend back to lie along [0001] and thread to the surface. In addition, three other sets of dislocations were observed. The first set consists of a wall of parallel dislocations lying in the coalescence plane and nearly parallel to the substrate, with Burgers vector (b) in the (0001) plane. The second set is comprised of rectangular loops with b = 1/3 [110] (perpendicular to the coalescence boundary) which originate in the coalescence boundary and extend laterally into the film on the (100). The third set of dislocations threads laterally through the film along the [100] bar axis with 1/3<110>-type Burgers vectors These sets result in a dislocation density of ∼109 cm−2. High resolution X-ray reciprocal space maps indicate wing tilt of ∼0.5º.

Investigation of Residual Strains of the Second Kind in Plastically Deformed Metallic Materials

1994 ◽  
Vol 376 ◽  
Author(s):  
M. Vrána ◽  
P. Klimanek ◽  
T. Kschidock ◽  
P. Lukáš ◽  
P. Mikula
Keyword(s):  
High Resolution ◽  
Neutron Diffraction ◽  
Stacking Faults ◽  
Metallic Materials ◽  
Line Broadening ◽  
X Ray Diffraction ◽  
X Ray ◽  
Neutron Diffractometer ◽  
Residual Strains ◽  
Good Agreement

ABSTRACTInvestigation of strongly distorted crystal structures caused by dislocations, stacking-faults etc. in both plastically deformed f.c.c. and b.c.c. metallic materials was performed by the analysis of the neutron diffraction line broadening. Measurements were realized by means of the high resolution triple-axis neutron diffractometer equipped by bent Si perfect crystals as monochromator and analyzer at the NPI Řež. The substructure parameters obtained in this manner are in good agreement with the results of X-ray diffraction analysis.

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