X-ray-scattering analysis of surface structures produced by vapor-phase epitaxy of GaAs

1994 ◽  
Vol 49 (3) ◽  
pp. 1957-1965 ◽  
Author(s):  
F. J. Lamelas ◽  
P. H. Fuoss ◽  
D. W. Kisker ◽  
G. B. Stephenson ◽  
P. Imperatori ◽  
...  
Keyword(s):  
Vapor Phase ◽  
Vapor Phase Epitaxy ◽  
Surface Structures ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

Application of x-ray scattering to the in-situ study of organometallic vapor phase epitaxy

1990 ◽  
Author(s):  
David W. Kisker ◽  
Paul H. Fuoss ◽  
Goullioud Renaud ◽  
K. L. Tokuda ◽  
Sean Brennan ◽  
...  
Keyword(s):  
Vapor Phase ◽  
Vapor Phase Epitaxy ◽  
Organometallic Vapor Phase Epitaxy ◽  
X Ray ◽  
In Situ Study ◽  
X Ray Scattering ◽  
Ray Scattering

Atomic scale characterization of organometallic vapor phase epitaxial growth using in-situ grazing incidence X-ray scattering

1992 ◽  
Vol 124 (1-4) ◽  
pp. 1-9 ◽  
Author(s):  
D.W. Kisker ◽  
G.B. Stephenson ◽  
P.H. Fuoss ◽  
F.J. Lamelas ◽  
S. Brennan ◽  
...  
Keyword(s):  
Epitaxial Growth ◽  
Vapor Phase ◽  
Grazing Incidence ◽  
Atomic Scale ◽  
X Ray ◽  
X Ray Scattering ◽  
Scale Characterization ◽  
Ray Scattering

Application of X-Ray Scattering to the in Situ Study of Organometallic Vapor Phase Epitaxy

1988 ◽  
Vol 131 ◽  
Author(s):  
P. H. Fuoss ◽  
D. W. Kisker ◽  
S. Brennan ◽  
J. L. Kahn
Keyword(s):  
Vapor Phase ◽  
Atmospheric Pressure ◽  
Chemical Vapor ◽  
High Signal ◽  
X Ray ◽  
Surface Sensitivity ◽  
X Ray Scattering ◽  
Detailed Surface ◽  
Ray Scattering

ABSTRACTDespite their importance, the detailed surface reactions and rearrangements which occur during chemical vapor deposition remain largely undetermined because of the lack of suitable experimental probes. In principle, x-ray scattering and spectroscopy techniques are well suited to studying these near atmospheric pressure processes but advances in this area have been limited both by the lack of suitable x-ray sources and by the difficulty of integrating the growth and measurement experiments. We have developed equipment and techniques to perform in situ x-ray scattering studies of the structure of surfaces during organometallic vapor phase epitaxial (OMVPE) growth using the extremely bright undulator radiation from the PEP electron storage ring. In this paper, we describe our initial experimental results studying cleaning and subsequent reconstruction of GaAs (001) surfaces in a flowing H2 ambient. These results demonstrate the excellent surface sensitivity, low background and high signal levels necessary to study the dynamic processes associated with semiconductor growth using OMVPE.

scholarly journals X-ray Reflectometry and Related Surface Near X-ray Scattering Methods

2014 ◽  
Vol 228 (10-12) ◽  
Author(s):  
Oliver H. Seeck
Keyword(s):  
Grazing Incidence ◽  
Surface Structures ◽  
Wave Optics ◽  
Near Surface ◽  
X Ray ◽  
Full Theory ◽  
X Ray Scattering ◽  
Grazing Incidence Diffraction ◽  
Non Destructive ◽  
Ray Scattering

AbstractSurface sensitive X-ray scattering methods are mostly non-destructive tools which are frequently used to investigate the nature of thin films, interfaces and artificial near surface structures. Discussed here are diffraction based methods, namely reflectometry and the related techniques grazing incidence diffraction and crystal truncation rod measurements. For the experiment, an X-ray beam is diffracted from surface near structures of the sample and detected by adequate detectors. To analyze the data the according X-ray scattering theory has to be applied. The full theory of surface sensitive X-ray scattering is complex and based on general considerations from wave optics. However, instructive insights into the scattering processes are provided by the Born-approximation which in many cases yields sufficient results. The methods are applied to solve the structure of a mercury-electrolyte interface during a chemical reaction and to determine the strain distribution in surface near SiGe quantum dots.

scholarly journals In Situ Monitoring of Laser-Induced Periodic Surface Structures Formation on Polymer Films by Grazing Incidence Small-Angle X-ray Scattering

Langmuir ◽  
2015 ◽  
Vol 31 (13) ◽  
pp. 3973-3981 ◽  
Author(s):  
Esther Rebollar ◽  
Daniel R. Rueda ◽  
Ignacio Martín-Fabiani ◽  
Álvaro Rodríguez-Rodríguez ◽  
Mari-Cruz García-Gutiérrez ◽  
...  
Keyword(s):  
Polymer Films ◽  
Small Angle ◽  
Grazing Incidence ◽  
Surface Structures ◽  
In Situ Monitoring ◽  
Periodic Surface ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

Microtubule nucleation sequence studied by time-resolved x-ray scattering and electron microscopy

1983 ◽  
Vol 41 ◽  
pp. 766-767
Author(s):  
Eva-Maria Mandelkow ◽  
Eckhard Mandelkow ◽  
Joan Bordas
Keyword(s):  
Electron Microscopy ◽  
Dynamic Equilibrium ◽  
Time Resolved ◽  
X Ray ◽  
Additional Information ◽  
X Ray Scattering ◽  
Low Concentrations ◽  
Microtubule Growth ◽  
Ray Patterns ◽  
Ray Scattering

When a solution of microtubule protein is changed from non-polymerising to polymerising conditions (e.g. by temperature jump or mixing with GTP) there is a series of structural transitions preceding microtubule growth. These have been detected by time-resolved X-ray scattering using synchrotron radiation, and they may be classified into pre-nucleation and nucleation events. X-ray patterns are good indicators for the average behavior of the particles in solution, but they are difficult to interpret unless additional information on their structure is available. We therefore studied the assembly process by electron microscopy under conditions approaching those of the X-ray experiment. There are two difficulties in the EM approach: One is that the particles important for assembly are usually small and not very regular and therefore tend to be overlooked. Secondly EM specimens require low concentrations which favor disassembly of the particles one wants to observe since there is a dynamic equilibrium between polymers and subunits.

Time-Resolved Cryo-Electron Microscopy of Oscillating Microtubules

1990 ◽  
Vol 48 (1) ◽  
pp. 502-503
Author(s):  
Eva-Maria Mandelkow ◽  
Ron Milligan
Keyword(s):  
Electron Microscopy ◽  
Dynamic Instability ◽  
Entire Solution ◽  
Reaction Scheme ◽  
Time Resolved ◽  
X Ray ◽  
X Ray Scattering ◽  
A Chain ◽  
Ray Scattering

Microtubules form part of the cytoskeleton of eukaryotic cells. They are hollow libers of about 25 nm diameter made up of 13 protofilaments, each of which consists of a chain of heterodimers of α-and β-tubulin. Microtubules can be assembled in vitro at 37°C in the presence of GTP which is hydrolyzed during the reaction, and they are disassembled at 4°C. In contrast to most other polymers microtubules show the behavior of “dynamic instability”, i.e. they can switch between phases of growth and phases of shrinkage, even at an overall steady state [1]. In certain conditions an entire solution can be synchronized, leading to autonomous oscillations in the degree of assembly which can be observed by X-ray scattering (Fig. 1), light scattering, or electron microscopy [2-5]. In addition such solutions are capable of generating spontaneous spatial patterns [6].In an earlier study we have analyzed the structure of microtubules and their cold-induced disassembly by cryo-EM [7]. One result was that disassembly takes place by loss of protofilament fragments (tubulin oligomers) which fray apart at the microtubule ends. We also looked at microtubule oscillations by time-resolved X-ray scattering and proposed a reaction scheme [4] which involves a cyclic interconversion of tubulin, microtubules, and oligomers (Fig. 2). The present study was undertaken to answer two questions: (a) What is the nature of the oscillations as seen by time-resolved cryo-EM? (b) Do microtubules disassemble by fraying protofilament fragments during oscillations at 37°C?

X-ray scattering by 1D molecular Guinier-Preston zones in ordered smectic phases

1992 ◽  
Vol 2 (6) ◽  
pp. 899-913 ◽  
Author(s):  
Patrick Davidson ◽  
Elisabeth Dubois-Violette ◽  
Anne-Marie Levelut ◽  
Brigitte Pansu
Keyword(s):  
X Ray ◽  
X Ray Scattering ◽  
Smectic Phases ◽  
Ray Scattering
Sign in / Sign up

Export Citation Format

Share Document