Determination of the wurtzite content and orientation distribution of nanowire ensembles

2009 ◽  
Vol 1206 ◽  
Author(s):  
Dominik Kriegner ◽  
Mario Keplinger ◽  
Julian Stangl ◽  
Aaron M. Andrews ◽  
Pavel Klang ◽  
...  
Keyword(s):  
Lattice Constant ◽  
Orientation Distribution ◽  
Growth Direction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Pole Figures

AbstractWe present x-ray diffraction based methods to quantitatively determine the wurtzite content of nanowire ensembles and to investigate the effect of twinning. An increased lattice constant in growth direction is found for all investigated InAs and InP nanowire samples. This increase is independent of the wurtzite content. Using x-ray pole figures we find that twinning is present in GaAs/Si branched nanowires, which leads to 60° rotations of the lattice.

X-Ray Diffraction Investigation of Electrochemically Deposited Copper

2004 ◽  
Vol 443-444 ◽  
pp. 201-204 ◽  
Author(s):  
Karen Pantleon ◽  
Jens Dahl Jensen ◽  
Marcel A.J. Somers
Keyword(s):  
Process Parameters ◽  
Orientation Distribution ◽  
Distribution Functions ◽  
Organic Additives ◽  
X Ray Diffraction ◽  
X Ray ◽  
Pole Figures ◽  
Electrochemically Deposited ◽  
Cu Interconnect

Copper layers were deposited from acidic electrolytes containing different amounts of organic additives, designed for the formation of Cu-interconnect structures. Amorphous Ni-P substrates allow to study the unbiased growth of the electrodeposits. The crystallographic texture was investigated by the determination of X-ray diffraction (XRD) pole figures and the calculation of the orientation distribution functions. XRD results are discussed in relation to the morphologies of the electrodeposits as investigated with light optical microscopy and correlated with the process parameters during electrodeposition.

Textures Applied to Mechanical Processing Technology Assessment in Ancient Bronze

2005 ◽  
Vol 495-497 ◽  
pp. 719-724
Author(s):  
R.E. Bolmaro ◽  
B. Molinas ◽  
E. Sentimenti ◽  
A.L. Fourty
Keyword(s):  
Orientation Distribution ◽  
Distribution Functions ◽  
Archaeological Sites ◽  
Mechanical Processing ◽  
Post Processing ◽  
X Ray Diffraction ◽  
Mechanical Process ◽  
X Ray ◽  
Pole Figures ◽  
Microscopic Inspection

Some ancient metallic art craft, utensils, silverware and weapons are externally undistinguishable from modern ones. Not only the general aspect and shape but also some uses have not changed through the ages. Moreover, when just some small pieces can be recovered from archaeological sites, the samples can not easily be ascribed to any known use and consequently identified. It is clear that mechanical processing has changed along history but frequently only a "microscopic" inspection can distinguish among different techniques. Some bronze samples have been collected from the Quarto d’Altino (Veneto) archaeological area in Italy (paleovenetian culture) and some model samples have been prepared by a modern artisan. The sample textures have been measured by X-ray Diffraction techniques. (111), (200) and (220) pole figures were used to calculate Orientation Distribution Functions and further recalculate pole figures and inverse pole figures. The results were compared with modern forging technology results. Textures are able to discern between hammering ancient techniques for sheet production and modern industrial rolling procedures. However, as it is demonstrated in the present work, forgery becomes difficult to detect if the goldsmith, properly warned, proceeds to erase the texture history with some hammering post-processing. The results of this contribution can offer to the archaeologists the opportunity to take into consideration the texture techniques in order to discuss the origin (culture) of the pieces and the characteristic mechanical process developed by the ancient artisan. Texture can also help the experts when discussing the originality of a certain piece keeping however in mind the cautions indicated in this publication.

Absolute Präzisionsbestimmung von Gitterkonstanten an Germanium- und Aluminium-Einkristallen mit Elektroneninterferenzen

1967 ◽  
Vol 22 (1) ◽  
pp. 92-95 ◽  
Author(s):  
W. Witt
Keyword(s):  
Electron Diffraction ◽  
Lattice Constant ◽  
Bulk Material ◽  
X Ray Diffraction ◽  
Full Agreement ◽  
X Ray ◽  
Lattice Constants ◽  
Precision Determination ◽  
Subsequent Chemical

An absolute precision determination of lattice constants by electron diffraction is made with thin monocrystalline films of germanium and aluminium, having a thickness between 1000 and 5000 A. The films are prepared from the bulk material by mechanical polishing and subsequent chemical polishing or etching. The obtained values for the lattice constant α of both materials are within the accuracy Δα/α= ±3·10-5 of measurement in full agreement with the corresponding values obtained by X-ray diffraction (Smakula and Kalnajs).

Theoretical and experimental developments for accurate determination of crystallinity of cellulose I materials

2010 ◽  
Vol 44 (1) ◽  
pp. 184-192 ◽  
Author(s):  
Carlos Driemeier ◽  
Guilherme A. Calligaris
Keyword(s):  
Accurate Determination ◽  
Dry Weight ◽  
Orientation Distribution ◽  
X Ray Diffraction ◽  
Cellulose I ◽  
Experimental Development ◽  
X Ray ◽  
Pure Cellulose ◽  
Better Than

This work defines the crystallinity of cellulose I materials on a dry-weight basis. Theoretical and experimental developments in X-ray diffraction lead to a crystallinity determination method that is estimated to reach 1σ accuracies of better than 0.05 (crystallinity defined between 0 and 1). The method is based on Rietveld modelling, to resolve cellulose I Bragg peaks, and a standard truncated invariant integral. Corrections are derived to account for incoherent scattering, moisture content and other compositional deviations from pure cellulose. The experimental development uses X-ray diffraction in transmission fibre geometry with two-dimensional pattern Rietveld modelling, including a crystal-orientation distribution function. The crystallinities of a few commercial cellulose I materials were determined with the aim of illustrating the applicability of the method.

Critical evaluation of the Lotgering degree of orientation texture indicator

2004 ◽  
Vol 19 (11) ◽  
pp. 3414-3422 ◽  
Author(s):  
Jacob L. Jones ◽  
Elliott B. Slamovich ◽  
Keith J. Bowman
Keyword(s):  
Bismuth Titanate ◽  
Critical Evaluation ◽  
Orientation Distribution ◽  
X Ray Diffraction ◽  
Standard Unit ◽  
X Ray ◽  
Pole Figures ◽  
Textured Ceramics ◽  
Degree Of Orientation ◽  
Tape Cast

Preferred orientation in textured ceramics is often assessed by comparing the relative intensities of x-ray diffraction reflections to those of a randomly oriented ceramic using the Lotgering degree of orientation (f). However, this paper provides evidence that indiscriminate assessments of f can be misleading. Using measured intensities of a modestly textured tape cast bismuth titanate (Na0.5Bi4.5Ti4O15) ceramic, calculated f values vary from 7.4 to 73.2% depending on the reflections included in the calculation. The texture is also quantified by calculating the orientation distribution function (ODF) using measured pole figures. A model is then presented that demonstrates f is nonlinear with the multiple of preferred (00l)-orientations, the standard unit of the 00l pole figure.

Preferred crystallographic orientation in mature and juvenile wood

2007 ◽  
Vol 222 (3-4) ◽  
Author(s):  
Jan T. Bonarski ◽  
Wieslaw Olek
Keyword(s):  
Distribution Function ◽  
Juvenile Wood ◽  
Microfibril Angle ◽  
Orientation Distribution ◽  
Experimental Methods ◽  
X Ray Diffraction ◽  
Traditional Concept ◽  
X Ray ◽  
Pole Figures ◽  
The Mean

Investigations of the crystallograpically organized regions of mature and juvenile Scots pine wood were performed. Experimental methods of X-ray diffraction were applied. Incomplete pole figures were measured, in order to calculate the orientation distribution function. The differences in the texture of the mature and juvenile wood were determined. The traditional concept of the mean microfibril angle was enhanced by developing the misorientation parameters. Evident differences in the space arrangement of cellulose of the both zones of wood were identified and described.

A Computer-Controlled X-Ray Diffractometer for Texture Studies of Polycrystalline Materials

1968 ◽  
Vol 12 ◽  
pp. 404-417 ◽  
Author(s):  
C. Richard Desper
Keyword(s):  
Computer Control ◽  
Orientation Distribution ◽  
Small Time ◽  
Polycrystalline Materials ◽  
Time Sharing ◽  
X Ray ◽  
Pole Figures ◽  
Continuous Scanning ◽  
Legendre Expansion

AbstractThe Picker Four-Angle Computer System (FACS-1), a computercontrolled x-ray diffractometer originally designed for single crystal studies, has been adapted for use with polycrystalline samples. The system is controlled by a PDP-8S, a small time-sharing computer with teletype input and output. Programs have been written to take advantage of the high degree of flexibility inherent in online computer control. Four basic operations are possible: (a) simple 2θ step-scanning with variable step width; (b) 2θ stepscanning with randomization of orientation; (c) determination of Legendre expansion coefficients for oriented specimens; and (d) determination of pole figures. In operation (a), data is gathered at a series of 2θ values at a prefixed count and/or time. In (b), the sample is rotated to average out orientation, giving the “randomized” intensity (2θ) at various 2θ values. The on-line computer reads the scaler and timer every two degrees of x rotation and forms the appropriate integrals for calculating (2θ) as the sample rotates. Operation (c) is an extension of (b): not only is (2θ) determined, but also various moments of the orientation distribution of the form , where Pn is the nth order Legendre polynomial. Operation (d) may be used to measure pole figures of sheet specimens in reflection or transmission, or of fibers or small particles. Optional modes of operation allow for (a) use of the Ross “balanced filter” technique; (b) integration across diffraction peaks by continuous scanning in 2θ, with background correction; and (c) application of absorption corrections.

scholarly journals Texture and Lamellae Distribution Functions in Lamellar Eutectics

1986 ◽  
Vol 6 (4) ◽  
pp. 265-287 ◽  
Author(s):  
H. J. Bunge
Keyword(s):  
Three Dimensional ◽  
Orientation Distribution ◽  
Distribution Functions ◽  
X Rays ◽  
Two Dimensional ◽  
Absorption Factor ◽  
X Ray Diffraction ◽  
Diffraction Vector ◽  
X Ray ◽  
Pole Figures

The crystallographic orientation distribution and the geometrical lamellae orientation distribution in lamellar eutectics are, in general, not independent of each other. The combined orientation-lamellae distribution function depends on five angular parameters. X-ray diffraction in such eutectics may exhibit an anisotropic macroscopic absorption factor if the penetration depth of the X-rays is large compared with their planar size. As a consequence, the reflected X-ray intensity may depend on a third angle γ, i.e. a rotation of the sample about the diffraction vector s additionally to the usual pole figure angles α, β which describe the orientation of the diffraction vector s with respect to the sample coordinate system. It is thus necessary to measure three-dimensional generalized pole figures instead of conventional two-dimensional ones.

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