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.

Diffraction analysis of perovskite-like oxides containing irregular intergrowths

2008 ◽  
Vol 42 (1) ◽  
pp. 1-9 ◽  
Author(s):  
L. Olikhovska ◽  
A. Ustinov
Keyword(s):  
Stacking Faults ◽  
Lattice Parameter ◽  
Stacking Fault ◽  
Layered Perovskite ◽  
Structural Fragment ◽  
X Ray Diffraction ◽  
X Ray ◽  
Fault Properties ◽  
Diffraction Peaks ◽  
Position Profile

Features of the X-ray intensity distributions caused by the presence of random and nonrandom stacking faults (irregular intergrowths) in layered perovskite-like oxides are studied by a computer simulation technique. It is shown that, apart from the stacking fault properties, the position, profile and intensity of a diffraction peak are dependent on the ratio between theclattice parameter of the crystal and the thickness of the new structural fragment formed as a result of the stacking fault. A means of characterizing the stacking faults on the basis of the relative positions of pairs of diffraction peaks is presented. The approach is exemplified by the X-ray diffraction study of a disordered single crystal of the system Bi–Sr–Ca–Cu–O.

Powder diffraction analysis of an interstratified marcasite/pyrite structure

1995 ◽  
Vol 10 (3) ◽  
pp. 198-203 ◽  
Author(s):  
Neil E. Johnson ◽  
Sidney S. Pollack ◽  
Elizabeth A. Frommell ◽  
Patricia A. Eldredge
Keyword(s):  
Catalytic Activity ◽  
Stacking Faults ◽  
Catalyst Precursor ◽  
X Ray Diffraction ◽  
Aromatic Rings ◽  
X Ray ◽  
Naturally Occurring ◽  
Benzylic Carbon ◽  
Diffraction Peaks ◽  
Diffraction Patterns

A synthetic catalyst precursor formed by sulfiding ferrihydrite (Fe3+O(OH)) in the presence of a hydrogen donor produces X-ray diffraction patterns resembling a mixture of both naturally occurring FeS2 polymorphs marcasite and pyrite. The diffraction peaks display a differential broadening, however, wherein only those peaks coincident to both marcasite and pyrite are strong and sharp, a feature that cannot be accounted for by a simple physical mixture. The broadening is analogous to that found in hexagonal cobalt, where occasional stacking faults produce interstratification of the hexagonal and cubic close-packed forms, resulting in strongly coherent diffraction only along the stacking direction. The crystal structures of marcasite and pyrite are virtually identical if viewed perpendicular to the (101) and (001) planes, respectively. Calculation of diffraction patterns based upon models of interstratifying marcasite and pyrite layers along these planes demonstrates that a sequence with marcasite-to-pyrite and pyrite-to-marcasite stacking fault probabilities of 0.22 provides a good fit to the experimental pattern. This interstratified material is a precursor to a species that shows catalytic activity for cleaving C-C bonds between aromatic rings and benzylic carbon atoms at low (<350 °C) temperatures.

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.

X-Ray Diffraction (Pole Figure) Study of the Epitaxy of Gold Thin Films on GaAs

1982 ◽  
Vol 18 ◽  
Author(s):  
Siu Leung ◽  
A. G. Milnes ◽  
D. D. L. Chung
Keyword(s):  
Thin Films ◽  
Film Thickness ◽  
Pole Figure ◽  
Gold Films ◽  
X Ray Diffraction ◽  
Epitaxial Relationship ◽  
Lattice Match ◽  
X Ray ◽  
Perfect Lattice ◽  
Gold Thin Films

X-ray diffraction (pole figure) measurements were made on gold thin films (300–2300 Å) evaporated on GaAs{111} and GaAs{001} to investigate the heteroepitaxy and twinning of the gold films and the chemoepitaxy of Au7Ga2 on GaAs. For both GaAs orientations the epitaxial relationship (hkl)AU[hkl]Au/ (hkl)GaAs[hkl]GaAs was observed for all values of h, k and l. In addition, twin orientations were observed. For GaAs{111}, fourfold rotation twinning about the Au[l11] direction resulted in four azimuthal orientations: [112]Au // [112]GaAs, [112]Au// [112]GaAs, [112]Au// [110]GaAs, and [112]AU/ [110]GaAs. For GaAs{001}, reflection twinning with the four Au{111} planes as twinning planes resulted in four other orientations with Au(001) at approximately 71° from GaAs(001). The relative amounts of the twins depended on the substrate temperature, the film thickness and the deposition rate. Chemoepitaxy was observed for Au7Ga2 on GaAs{111} the epitaxial relationship was (111)Au/ (0110)Au7Ga2/(111)GaAsand Au7Ga2[0001] was off by 10° from GaAs[110], toward GaAs[011], i.e. Au7Ga2[0001] was off by 10° from Au[110], toward Au[011]. This relationship corresponds to a perfect lattice match between Au7Ga2 and gold.

Strain in Epitaxial BaTiO3 Thin Films Prepared by MOCVD

1998 ◽  
Vol 541 ◽  
Author(s):  
S. Chattopadhyay ◽  
A. Teren ◽  
B.W. Wessels
Keyword(s):  
Thin Films ◽  
Film Thickness ◽  
Full Width Half Maximum ◽  
Diffraction Peak ◽  
Full Width ◽  
Half Maximum ◽  
X Ray Diffraction ◽  
X Ray ◽  
Peak Broadening ◽  
Diffraction Peaks

AbstractThe microstrain in epitaxial BaTiO3 thin films has been investigated using x-ray diffraction. The full width half maximum of the (001) diffraction peaks ranged from 0.12 to 0.49 deg. From the analysis of the angular dependence of the diffraction peak broadening, it is concluded that the broadening is due predominantly to strain. The magnitude of the microstrain decreases sharply with increasing film thickness.

Structural Analysis of X-ray Diffraction Peaks of Thin Film Gallium Arsenide

1970 ◽  
Vol 14 ◽  
pp. 441-452
Author(s):  
E. J. Charlson ◽  
D. H. Hu ◽  
M. R. Farukhi
Keyword(s):  
Thin Film ◽  
Structural Analysis ◽  
Partial Pressure ◽  
Fourier Coefficients ◽  
Stacking Faults ◽  
Line Broadening ◽  
X Ray Diffraction ◽  
X Ray ◽  
Gaas Films ◽  
Diffraction Peaks

AbstractA least-squares polynomial approximation of the Warren-Averbach Fourier coefficients line broadening analysis has shown flash-evaporated GaAs films to be characterized by De(lll) ≤ 400 Å and >εL2<½ ⋍ 0.002. Though twinning is the dominant faulting mechanism, a considerable amount of single and double deformation stacking faults are also present. Growth under a partial pressure of arsenic and tin has enhanced crystallite size by a factor of four.

Defect structures of Nb1+αS2 sulfidation scales

1992 ◽  
Vol 50 (1) ◽  
pp. 38-39
Author(s):  
Chuxin Zhou ◽  
L. W. Hobbs
Keyword(s):  
Stacking Faults ◽  
Rhombohedral Structure ◽  
Stacking Sequence ◽  
Defect Structures ◽  
X Ray Diffraction ◽  
X Ray ◽  
Plane Normal ◽  
Lower Case ◽  
Sulfur Layer ◽  
Two Phases

One of the major purposes in the present work is to study the high temperature sulfidation properties of Nb in severe sulfidizing environments. Kinetically, the sulfidation rate of Nb is satisfactorily slow, but the microstructures and non-stoichiometry of Nb1+αS2 challenge conventional oxidation/sulfidation theory and defect models of non-stoichiometric compounds. This challenge reflects our limited knowledge of the dependence of kinetics and atomic migration processes in solid state materials on their defect structures.Figure 1 shows a high resolution image of a platelet from the middle portion of the Nb1+αS2 scale. A thin lamellar heterogeneity (about 5nm) is observed. From X-ray diffraction results, we have shown that Nb1+αS2 scale is principally rhombohedral structure, but 2H-NbS2 can result locally due to stacking faults, because the only difference between these 2H and 3R phases is variation in the stacking sequence along the c axis. Following an ABC notation, we use capital letters A, B and C to represent the sulfur layer, and lower case letters a, b and c to refer to Nb layers. For example, the stacking sequence of 2H phase is AbACbCA, which is a ∼12Å period along the c axis; the stacking sequence of 3R phase is AbABcBCaCA to form an ∼18Å period along the c axis. Intergrowth of these two phases can take place at stacking faults or by a shear in the basal plane normal to the c axis.

Control of the phase composition of advanced calcium phosphates using an x-ray diffractometer with a curved position-sensitive detector

2020 ◽  
Vol 86 (6) ◽  
pp. 29-35
Author(s):  
V. P. Sirotinkin ◽  
O. V. Baranov ◽  
A. Yu. Fedotov ◽  
S. M. Barinov
Keyword(s):  
Phase Composition ◽  
Calcium Phosphates ◽  
Position Sensitive Detector ◽  
Sensitive Detector ◽  
X Ray Diffraction ◽  
X Ray ◽  
Impurity Phases ◽  
Position Sensitive ◽  
Diffraction Peaks ◽  
Diffraction Patterns

The results of studying the phase composition of advanced calcium phosphates Ca10(PO4)6(OH)2, β-Ca3(PO4)2, α-Ca3(PO4)2, CaHPO4 · 2H2O, Ca8(HPO4)2(PO4)4 · 5H2O using an x-ray diffractometer with a curved position-sensitive detector are presented. Optimal experimental conditions (angular positions of the x-ray tube and detector, size of the slits, exposure time) were determined with allowance for possible formation of the impurity phases during synthesis. The construction features of diffractometers with a position-sensitive detector affecting the profile characteristics of x-ray diffraction peaks are considered. The composition for calibration of the diffractometer (a mixture of sodium acetate and yttrium oxide) was determined. Theoretical x-ray diffraction patterns for corresponding calcium phosphates are constructed on the basis of the literature data. These x-ray diffraction patterns were used to determine the phase composition of the advanced calcium phosphates. The features of advanced calcium phosphates, which should be taken into account during the phase analysis, are indicated. The powder of high-temperature form of tricalcium phosphate strongly adsorbs water from the environment. A strong texture is observed on the x-ray diffraction spectra of dicalcium phosphate dihydrate. A rather specific x-ray diffraction pattern of octacalcium phosphate pentahydrate revealed the only one strong peak at small angles. In all cases, significant deviations are observed for the recorded angular positions and relative intensity of the diffraction peaks. The results of the study of experimentally obtained mixtures of calcium phosphate are presented. It is shown that the graphic comparison of experimental x-ray diffraction spectra and pre-recorded spectra of the reference calcium phosphates and possible impurity phases is the most effective method. In this case, there is no need for calibration. When using this method, the total time for analysis of one sample is no more than 10 min.

scholarly journals Study on the Electrical, Structural, Chemical and Optical Properties of PVD Ta(N) Films Deposited with Different N2 Flow Rates

Coatings ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 937
Author(s):  
Yingying Hu ◽  
Md Rasadujjaman ◽  
Yanrong Wang ◽  
Jing Zhang ◽  
Jiang Yan ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Optical Properties ◽  
Photoelectron Spectroscopy ◽  
Crystal Size ◽  
Silicon Substrates ◽  
X Ray Diffraction ◽  
Dc Magnetron Sputtering ◽  
Flow Rates ◽  
X Ray ◽  
N2 Flow Rate

By reactive DC magnetron sputtering from a pure Ta target onto silicon substrates, Ta(N) films were prepared with different N2 flow rates of 0, 12, 17, 25, 38, and 58 sccm. The effects of N2 flow rate on the electrical properties, crystal structure, elemental composition, and optical properties of Ta(N) were studied. These properties were characterized by the four-probe method, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and spectroscopic ellipsometry (SE). Results show that the deposition rate decreases with an increase of N2 flows. Furthermore, as resistivity increases, the crystal size decreases, the crystal structure transitions from β-Ta to TaN(111), and finally becomes the N-rich phase Ta3N5(130, 040). Studying the optical properties, it is found that there are differences in the refractive index (n) and extinction coefficient (k) of Ta(N) with different thicknesses and different N2 flow rates, depending on the crystal size and crystal phase structure.

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