Silicon L2, 3-Edge Xanes Study of Platinum Silicide Thin Films

1996 ◽  
Vol 441 ◽  
Author(s):  
S. J. Naftel ◽  
T. K. Sham ◽  
S. R. Das ◽  
D.-X. Xu
Keyword(s):  
Fluorescence Yield ◽  
Detection Methods ◽  
Sampling Depth ◽  
Total Electron ◽  
Edge Structure ◽  
X Ray ◽  
Platinum Silicide ◽  
Depth Difference ◽  
Total Fluorescence ◽  
X Ray Absorption

AbstractPlatinum silicide films, with a typical thickness of several hundred Å, prepared on n-type Si(100) wafers by UHV mnagnetron sputter deposition followed by rapid thermal annealing, have been studied by Si L2,3-edge X-ray absorption near edge structure (XANES) using both total electron and total fluorescence yield detection. Samples of various annealing times were studied. XANES provides information on the electronic structure and morphology of the samples. By utilizing the sampling depth difference between the two detection methods, we can clearly see XANES data from each layer (eg. surface oxide, silicide) in the sample and can estimate the thickness of the oxide layer.

scholarly journals A zone-plate-based two-color spectrometer for indirect X-ray absorption spectroscopy

2019 ◽  
Vol 26 (4) ◽  
pp. 1266-1271 ◽  
Author(s):  
Florian Döring ◽  
Marcel Risch ◽  
Benedikt Rösner ◽  
Martin Beye ◽  
Philipp Busse ◽  
...  
Keyword(s):  
Absorption Spectroscopy ◽  
Fresnel Zone ◽  
Decay Channel ◽  
Chemical Properties ◽  
Fluorescence Yield ◽  
Complex Materials ◽  
X Ray ◽  
Total Fluorescence ◽  
X Ray Absorption

X-ray absorption spectroscopy (XAS) is a powerful element-specific technique that allows the study of structural and chemical properties of matter. Often an indirect method is used to access the X-ray absorption (XA). This work demonstrates a new XAS implementation that is based on off-axis transmission Fresnel zone plates to obtain the XA spectrum of La0.6Sr0.4MnO3 by analysis of three emission lines simultaneously at the detector, namely the O 2p–1s, Mn 3s–2p and Mn 3d–2p transitions. This scheme allows the simultaneous measurement of an integrated total fluorescence yield and the partial fluorescence yields (PFY) of the Mn 3s–2p and Mn 3d–2p transitions when scanning the Mn L-edge. In addition to this, the reduction in O fluorescence provides another measure for absorption often referred to as the inverse partial fluorescence yield (IPFY). Among these different methods to measure XA, the Mn 3s PFY and IPFY deviate the least from the true XA spectra due to the negligible influence of selection rules on the decay channel. Other advantages of this new scheme are the potential to strongly increase the efficiency and throughput compared with similar measurements using conventional gratings and to increase the signal-to-noise of the XA spectra as compared with a photodiode. The ability to record undistorted bulk XA spectra at high flux is crucial for future in situ spectroscopy experiments on complex materials.

On the origin of dips in total fluorescence yield X-ray absorption spectra: Partial and inverse partial fluorescence yield at the L-edge of cobalt aqueous solution

2012 ◽  
Vol 546 ◽  
pp. 164-167 ◽  
Author(s):  
Mikhail A. Soldatov ◽  
Kathrin M. Lange ◽  
Malte D. Gotz ◽  
Nicholas Engel ◽  
Ronny Golnak ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Absorption Spectra ◽  
Fluorescence Yield ◽  
X Ray ◽  
Total Fluorescence ◽  
X Ray Absorption

Fluorescence Yield Xanes and Exafs Experiments: Application to Highly Dilute and Surface Samples

1993 ◽  
Vol 37 ◽  
pp. 607-617 ◽  
Author(s):  
Glenn A. Waychunas ◽  
Gordon E. Brown
Keyword(s):  
Bound State ◽  
Fluorescence Yield ◽  
Interatomic Distances ◽  
Edge Structure ◽  
X Ray ◽  
Surface Samples ◽  
Radiation Sources ◽  
To Come ◽  
X Ray Absorption

The development of intense synchrotron radiation sources during the last twenty years has enabled several types of x-ray spectroscopy and scattering techniques to come into practical use. One of the most significant methods for the characterization of extremely dilute samples is high resolution x-ray absorption-edge spectroscopy. The technique is usually divided into two separate methods according to whether the x-ray absorption near edge structure (XANES) or the extended x-ray absorption fine structure (EXAFS) is analyzed. XANES features are due mainly to bound-state electronic transitions just below, and on the low energy side of the edge, and to multiple scattering resonances on the top of the edge and at somewhat higher energies. EXAFS features are oscillations due to ejected photoelectron back scattering interference processes in the close vicinity of the absorber atom. XANES analysis is used to determine atom valence, atom site distortion from regular geometries, and other details of the atom site. EXAFS features can be analyzed to recover interatomic distances between the absorber atom and its first few shells of neighbors, as well as the number and types of these neighbors. Together these techniques can provide an atomspecific probe of die short-range structure within almost any type of condensed matter.

X-Ray Absorption Fine Structure (Xafs) Studies Of Cobalt Silicide Thin Films

1998 ◽  
Vol 524 ◽  
Author(s):  
S. J. Naftel ◽  
I Coulthard ◽  
Y. Hu ◽  
T. K. Sham ◽  
M. Zinke-Allmang
Keyword(s):  
Thin Films ◽  
Fine Structure ◽  
Fluorescence Yield ◽  
Sputter Deposition ◽  
Cobalt Silicide ◽  
Total Electron ◽  
X Ray ◽  
Absorption Fine ◽  
Fine Structures ◽  
X Ray Absorption

ABSTRACTCobalt silicide thin films, prepared on Si(100) wafers, have been studied by X-ray absorption near edge structures (XANES) at the Si K-, L2,3 and Co K-edges utilizing both total electron (TEY) and fluorescence yield (FLY) detection as well as extended X-ray absorption fine structure (EXAFS) at the Co K-edge. Samples made using DC sputter deposition on clean Si surfaces and MBE were studied along with a bulk CoSi2 sample. XANES and EXAFS provide information about the electronic structure and morphology of the films. It was found that the films studied have essentially the same structure as bulk CoSi2. Both the spectroscopy and materials characterization aspects of XAFS (X-ray absorption fine structures) are discussed.

Silicate Formation at the Interface of high-k dielectrics and Si(001) Surfaces

2006 ◽  
Vol 917 ◽  
Author(s):  
Dieter Schmeisser ◽  
F. Zheng ◽  
F.J. Himpsel ◽  
H.J. Engelmann
Keyword(s):  
High Sensitivity ◽  
Fluorescence Yield ◽  
Gate Stacks ◽  
Total Electron ◽  
Silicate Formation ◽  
High K ◽  
Total Fluorescence ◽  
Characteristic Features ◽  
X Ray Absorption

AbstractThe composition and chemical bonding of the first atoms across the interface between Si(001) and the dielectric determine the quality of dielectric gate stacks. An analysis of that hidden interface is a challenge as it requires both, high sensitivity and elemental and chemical state information. We used SR based photoelectron spectroscopies and, in particular, X-ray absorption spectroscopy in total electron yield and total fluorescence yield at the Si2p and the O1s edges to address that issue. We report on results of Hf-oxide prepared by ALD and compare to Pr2O3 / Si(001), and compare the two to the SiO2 / Si(001) system as a reference. For both, Hf-oxide and Pr-oxide thin films we find evidence for the silicate formation at the interface as derived from the characteristic features at the Si2p and the O1s edges.

Measuring partial fluorescence yield using filtered detectors

2014 ◽  
Vol 21 (4) ◽  
pp. 716-721 ◽  
Author(s):  
T. D. Boyko ◽  
R. J. Green ◽  
A. Moewes ◽  
T. Z. Regier
Keyword(s):  
Dead Time ◽  
Collection Efficiency ◽  
Fluorescence Yield ◽  
Photon Flux ◽  
Linear Attenuation Coefficient ◽  
Edge Structure ◽  
X Ray ◽  
Energy Discrimination ◽  
Energy Dependent ◽  
X Ray Absorption

Typically, X-ray absorption near-edge structure measurements aim to probe the linear attenuation coefficient. These measurements are often carried out using partial fluorescence yield techniques that rely on detectors having photon energy discrimination improving the sensitivity and the signal-to-background ratio of the measured spectra. However, measuring the partial fluorescence yield in the soft X-ray regime with reasonable efficiency requires solid-state detectors, which have limitations due to the inherent dead-time while measuring. Alternatively, many of the available detectors that are not energy dispersive do not suffer from photon count rate limitations. A filter placed in front of one of these detectors will make the energy-dependent efficiency non-linear, thereby changing the responsivity of the detector. It is shown that using an array of filtered X-ray detectors is a viable method for measuring soft X-ray partial fluorescence yield spectra without dead-time. The feasibility of this technique is further demonstrated using α-Fe2O3as an example and it is shown that this detector technology could vastly improve the photon collection efficiency at synchrotrons and that these detectors will allow experiments to be completed with a much lower photon flux reducing X-ray-induced damage.

Determination of the Anomalous Scattering Factors in the Soft-X-ray Range using Diffraction from a Multilayer

1998 ◽  
Vol 31 (5) ◽  
pp. 700-707 ◽  
Author(s):  
L. Sève ◽  
J. M. Tonnerre ◽  
D. Raoux
Keyword(s):  
Fluorescence Yield ◽  
Bragg Diffraction ◽  
Anomalous Scattering ◽  
Total Electron Yield ◽  
Total Electron ◽  
X Ray ◽  
Scattering Factor ◽  
X Ray Absorption ◽  
Kronig Relation

Bragg diffraction from an Ag/Ni multilayer was used to determine independently both the real and imaginary parts of the anomalous scattering factor (ASF) around the NiLIIIandLIIedges in the soft-X-ray range. Huge resonant variations were observed with f'' reaching 55\,r_o and f' decreasing to −63 r_o at the NiLIIIedge. The independent measurements of f' and f'' are tested for coherency using the Kramers–Kronig relation. The f'' values are also compared with those derived from X-ray absorption methods such as total electron yield and fluorescence yield measurements.

XAS STUDY OF (BaCuO2)2/(CaCuO2)n SUPERLATTICES

2000 ◽  
Vol 14 (25n27) ◽  
pp. 2628-2633
Author(s):  
S. COLONNA ◽  
F. ARCIPRETE ◽  
A. BALZAROTTI ◽  
G. BALESTRINO ◽  
P. G. MEDAGLIA ◽  
...  
Keyword(s):  
Fine Structure ◽  
Oxygen Vacancies ◽  
Fluorescence Yield ◽  
Octahedral Coordination ◽  
Apical Oxygen ◽  
Edge Structure ◽  
X Ray ◽  
Local Bonding ◽  
X Ray Absorption ◽  
Oxygen Atoms

EXAFS (Extended X-ray Absorption Fine Structure) and XANES (X-Ray Absorption Near Edge Structure) spectroscopies have been used to probe the local bonding of the artificially layered superconducting (BaCuO2)2/(CaCuO2)n (n = 2, 3, 4) superlattices. Fluorescence-yield measurements have been performed above the Cu and Ba K-edges. This study shows that the charge reservoir (CR) block of the Ba/Ca superlattice contains oxygen vacancies randomly distributed in the CuO2 planes and that the two apical oxygen atoms are displaced out of the Ba plane giving rise to buckled BaO planes. These oxygen atoms have a distorted pyramidal and octahedral coordination around Cu at Ba/Ca interface and in the (BaCuO2) block, respectively.

X-RAY ABSORPTION STUDY OF Mg1-xAlxB2 AT B K-EDGE

2002 ◽  
Vol 16 (11n12) ◽  
pp. 1619-1626 ◽  
Author(s):  
K.-D. TSUEI ◽  
H.-J. LIN ◽  
L.-C. LIN ◽  
T.-Y. HOU ◽  
H.-H. HSIEH ◽  
...  
Keyword(s):  
Room Temperature ◽  
Structural Phase ◽  
Fluorescence Yield ◽  
Absorption Study ◽  
Hole Filling ◽  
Al Doping ◽  
X Ray ◽  
Peak Intensity ◽  
Total Fluorescence ◽  
X Ray Absorption

We have measured B K-edge X-ray absorption spectra of Mg 1-x Al x B 2 (x=0.0 ~ 0.4) using bulk-sensitive total fluorescence yield (TFY) at room temperature and 30 K. In contrast to previous reports no peaks near 192 eV and 194 eV could be observed after repeated scraping, indicating their origin being due to surface contamination. These clean spectra show a peak right above the absorption threshold, anticipated from transition to the unoccupied B 2p states. Except in the intermediate Al doping range of x ~ 0.1 to 0.28 the threshold peak intensity decreases, consistent with pσ-hole filling. The increase of peak intensity in the intermediate range is correlated with structural phase transition.

Chemical and orientational imaging of polymeric samples

1994 ◽  
Vol 52 ◽  
pp. 68-69
Author(s):  
H. Ade ◽  
B. Hsiao ◽  
G. Mitchell ◽  
E. Rightor ◽  
A. P. Smith ◽  
...  
Keyword(s):  
Ethylene Terephthalate ◽  
National Laboratory ◽  
Brookhaven National Laboratory ◽  
Carbonyl Groups ◽  
Aromatic Rings ◽  
Edge Structure ◽  
X Ray ◽  
Scanning Transmission ◽  
Polymeric Samples ◽  
X Ray Absorption

We have used the Scanning Transmission X-ray Microscope at beamline X1A (X1-STXM) at Brookhaven National Laboratory (BNL) to acquire high resolution, chemical and orientation sensitive images of polymeric samples as well as point spectra from 0.1 μm areas. This sensitivity is achieved by exploiting the X-ray Absorption Near Edge Structure (XANES) of the carbon K edge. One of the most illustrative example of the chemical sensitivity achievable is provided by images of a polycarbonate/pol(ethylene terephthalate) (70/30 PC/PET) blend. Contrast reversal at high overall contrast is observed between images acquired at 285.36 and 285.69 eV (Fig. 1). Contrast in these images is achieved by exploring subtle differences between resonances associated with the π bonds (sp hybridization) of the aromatic groups of each polymer. PET has a split peak associated with these aromatic groups, due to the proximity of its carbonyl groups to its aromatic rings, whereas PC has only a single peak.

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