Structural Analysis of GaN and GaN/InGaN/GaN DH Structures on Sapphire (0001) Substrate Grown by MOCVD

1996 ◽  
Vol 449 ◽  
Author(s):  
Hisao Sato ◽  
Yoshiki Naoi ◽  
Shiro Sakai
Keyword(s):  
Structural Analysis ◽  
Film Thickness ◽  
Film Structure ◽  
Mosaic Structure ◽  
Lattice Structures ◽  
X Ray Diffraction ◽  
Reciprocal Space Mapping ◽  
X Ray ◽  
Double Heterostructures ◽  
20 Nm

ABSTRACTWe have investigated lattice structures of GaN and InGaN/GaN single-heterostructures (SH) and double-heterostructures (DH) by the reciprocal space mapping using X-ray diffraction technique from (0002) plane. For a single GaN layers, the transition of the film structure from grains with relatively independent orientation at about 0.3 μm followed by the coalescence at about 1 μm, to a uniform film with mosaic structure at 1.4 μm was clearly observed. For DH structure, ω-mode FWHMs both from InGaN (In composition approximately 7 %) and capping-GaN layers increased with increasing film thickness from 20 nm to 110 nm indicating the increased mosaic structure in the thick InGaN. We also observed the dislocation related to this increasing mosaic structure.

Electrical and Structural Properties of Thin Palladium Films

1986 ◽  
Vol 41 (4) ◽  
pp. 665-670 ◽  
Author(s):  
R. Anton ◽  
K. Häupl ◽  
P. Rudolf ◽  
P. Wißmann
Keyword(s):  
Electrical Resistivity ◽  
Film Thickness ◽  
Statistical Model ◽  
Structural Information ◽  
Film Structure ◽  
X Ray Diffraction ◽  
Continuous Film ◽  
X Ray ◽  
Amorphous Substrates ◽  
Steep Decrease

The electrical resistivity of thin palladium films deposited on amorphous substrates is measured in dependence on film thickness. The data are interpreted with the help of a statistical model taking into account structural information obtained from AES, TEM and x-ray diffraction texture analysis. The steep decrease of resistivity in the ultra-thin thickness region can be immediately correlated with the formation of coherent areas in the films. A more flattened course is reached at about 8 nm thickness where a continuous film structure develops.

Turnover of Texture in low rate Sputter-Deposited Nanocrystalline Molybdenum Films

1997 ◽  
Vol 472 ◽  
Author(s):  
Tilo P. Drüsedau ◽  
Frank Klabunde ◽  
Mirko Lohmann ◽  
Thomas Hempel ◽  
Jurgen Bläsing
Keyword(s):  
Film Thickness ◽  
Fiber Texture ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Sputter Deposited ◽  
20 Nm ◽  
Low Rate ◽  
Erosion Zone

ABSTRACTThe crystallite size and orientation in molybdenum films prepared by magnetron sputtering at a low rate of typical 1 Å/s and a pressure of 0.45 Pa was investigated by X-ray diffraction and texture analysis. The surface topography was studied using atomic force microscopy. Increasing the film thickness from 20 nm to 3 μm, the films show a turnover from a (110) fiber texture to a (211) mosaic-like texture. In the early state of growth (20 nm thickness) the development of dome-like structures on the surface is observed. The number of these structures increases with film thickness, whereas their size is weakly influenced. The effect of texture turnover is reduced by increasing the deposition rate by a factor of six, and it is absent for samples mounted above the center of the magnetron source. The effect of texture turnover is related to the bombardment of the films with high energetic argon neutrals resulting from backscattering at the target under oblique angle and causing resputtering. Due to the narrow angular distribution of the reflected argon, bombardment of the substrate plane is inhomogeneous and only significant for regions close to the erosion zone of the magnetron.

Die Struktur epitaktisch aufgedampfter Goldfilme

1976 ◽  
Vol 31 (2) ◽  
pp. 183-189 ◽  
Author(s):  
W. Fischer ◽  
P. Wißmann
Keyword(s):  
Film Thickness ◽  
Angular Displacement ◽  
Stacking Faults ◽  
Film Structure ◽  
Silicon Substrates ◽  
Gold Films ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diffraction Peaks ◽  
Lattice Distortions

Abstract Gold films of 400 Å thickness were evaporated under UHV-conditions on (111)-, (110)-and (100)-oriented silicon substrates and were subsequently investigated by x-ray diffraction. Mainly the influence of orientation and cleanliness of the substrate on film structure was studied.Informations on the orientation and size of the crystallites as well as on lattice distortions were obtained by analysing intensity, angular displacement and width of the diffraction peaks. It is found that the gold films show a preferred (111)-orientation in all cases; only the degree of orienta-tion changes with the pretreatment of the substrate. The size of the (111)-oriented crystallites cor-responds to the film thickness, and a noticeable density of intrinsic stacking faults can be detected.

RNA polymerase: Preparation and structural analysis of helical polymers

1984 ◽  
Vol 42 ◽  
pp. 152-153
Author(s):  
E. Loren Buhle ◽  
Pamela Rew ◽  
Ueli Aebi
Keyword(s):  
Structural Analysis ◽  
Rna Polymerase ◽  
Molecular Level ◽  
X Ray Diffraction ◽  
Helical Polymers ◽  
X Ray ◽  
E Coli ◽  
The Past ◽  
Ordered Arrays ◽  
Low Ionic Strength

While DNA-dependent RNA polymerase represents one of the key enzymes involved in transcription and ultimately in gene expression in procaryotic and eucaryotic cells, little progress has been made towards elucidation of its 3-D structure at the molecular level over the past few years. This is mainly because to date no 3-D crystals suitable for X-ray diffraction analysis have been obtained with this rather large (MW ~500 kd) multi-subunit (α2ββ'ζ). As an alternative, we have been trying to form ordered arrays of RNA polymerase from E. coli suitable for structural analysis in the electron microscope combined with image processing. Here we report about helical polymers induced from holoenzyme (α2ββ'ζ) at low ionic strength with 5-7 mM MnCl2 (see Fig. 1a). The presence of the ζ-subunit (MW 86 kd) is required to form these polymers, since the core enzyme (α2ββ') does fail to assemble into such structures under these conditions.

Structural analysis by X-ray diffraction of a non-polar alkenyl liquid crystalline compound

1996 ◽  
Vol 20 (6) ◽  
pp. 765-770 ◽  
Author(s):  
A. Nath ◽  
S. Gupta ◽  
P. Mandal ◽  
S. Paul ◽  
H. Schenk
Keyword(s):  
Structural Analysis ◽  
Liquid Crystalline ◽  
Crystalline Compound ◽  
X Ray Diffraction ◽  
X Ray ◽  
Liquid Crystalline Compound

scholarly journals X-ray Diffraction: A Powerful Technique for the Multiple-Length-Scale Structural Analysis of Nanomaterials

Crystals ◽  
2016 ◽  
Vol 6 (8) ◽  
pp. 87 ◽  
Author(s):  
Cinzia Giannini ◽  
Massimo Ladisa ◽  
Davide Altamura ◽  
Dritan Siliqi ◽  
Teresa Sibillano ◽  
...  
Keyword(s):  
Structural Analysis ◽  
Length Scale ◽  
X Ray Diffraction ◽  
X Ray ◽  
Powerful Technique ◽  
Multiple Length Scale

Detection of mosaic structure in heteroepitaxial systems by microbeam X-ray diffraction

1970 ◽  
Vol 2 (3) ◽  
pp. K135-K136
Author(s):  
L. Varga ◽  
B. Szentpáli ◽  
I. Bertóti
Keyword(s):  
Mosaic Structure ◽  
X Ray Diffraction ◽  
X Ray

Synthesis, Structural, Morphological and I-V Characteristics of Polyaniline-MgCl Composite

2022 ◽  
Vol 1048 ◽  
pp. 141-146
Author(s):  
Madihally Nagaraja ◽  
Geetha Thippeswamy ◽  
Sushma Prashanth ◽  
Jayadev Pattar ◽  
Mahesh Hampapatna Mahesh
Keyword(s):  
Structural Analysis ◽  
Oxidative Polymerization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sem Micrographs ◽  
Morphological Studies ◽  
Current Voltage ◽  
Amorphous Nature ◽  
Diffraction Patterns ◽  
Polymerization Method

Composite of polyaniline-MgCl has been synthesized using oxidative polymerization method. Synthesized samples were characterized for structural analysis using FTIR and XRD. Morphological studies were carried by SEM micrographs. Current-Voltage (I-V) properties are obtained through Kiethly source meter. FTIR spectrum of polyaniline-MgCl composite indicates all the characteristic peaks of polyaniline. X-ray diffraction patterns represented the amorphous nature of polyaniline-MgCl composite. SEM micrographs confirmed the presence of MgCl particles in polyaniline matrix. I-V characteristics have shown the ohmic type behavior of polyaniline and polyaniline-MgCl composite.

Sign in / Sign up

Export Citation Format

Share Document