Characterization of As-doped, p-type ZnO by x-ray absorption near-edge structure spectroscopy: Theory

2006 ◽  
Vol 89 (22) ◽  
pp. 222113 ◽  
Author(s):  
Sukit Limpijumnong ◽  
M. F. Smith ◽  
S. B. Zhang
Keyword(s):  
X Ray ◽  
P Type ◽  
2006 ◽  
Vol 88 (11) ◽  
pp. 112103 ◽  
Author(s):  
Veeramuthu Vaithianathan ◽  
Byung-Teak Lee ◽  
Chang-Hwan Chang ◽  
Kandasami Asokan ◽  
Sang Sub Kim
Keyword(s):  
X Ray ◽  
P Type ◽  

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Yiming Chen ◽  
Chi Chen ◽  
Chen Zheng ◽  
Shyam Dwaraknath ◽  
Matthew K. Horton ◽  
...  

AbstractThe L-edge X-ray Absorption Near Edge Structure (XANES) is widely used in the characterization of transition metal compounds. Here, we report the development of a database of computed L-edge XANES using the multiple scattering theory-based FEFF9 code. The initial release of the database contains more than 140,000 L-edge spectra for more than 22,000 structures generated using a high-throughput computational workflow. The data is disseminated through the Materials Project and addresses a critical need for L-edge XANES spectra among the research community.


2006 ◽  
Vol 6 (11) ◽  
pp. 3422-3425
Author(s):  
Veeramuthu Vaithianathan ◽  
Jong Ha Moon ◽  
Chang-Hwan Chang ◽  
Kandasami Asokan ◽  
Sang Sub Kim

The electronic structure of laser-deposited P-doped ZnO films was investigated by X-ray absorption near-edge structure spectroscopy (XANES) at the O K-, Zn K-, and Zn L3-edges. While the O K-edge XANES spectrum of the n-type P-doped ZnO demonstrates that the density of unoccupied states, primarily O 2p–P 3sp hybridized states, is significantly high, the O K-edge XANES spectrum of the p-type P-doped ZnO shows a sharp decrease in intensity of the corresponding feature indicating that P replaces O sites in the ZnO lattice, and thereby generating PO. This produces holes to maintain charge neutrality that are responsible for the p-type behavior of P-doped ZnO. Both the Zn K-, and Zn L3-edge XANES spectra of the P-doped ZnO reveal that Zn plays no significant role in the p-type behavior of ZnO:P.


2012 ◽  
Vol 1475 ◽  
Author(s):  
Daniel J. Gregg ◽  
Yingjie Zhang ◽  
Zhaoming Zhang ◽  
Inna Karatchevtseva ◽  
Mark G. Blackford ◽  
...  

ABSTRACTA series of uranium-containing gadolinium zirconate samples have been fabricated at 1723 K in air. X-ray diffraction and Raman spectroscopy have confirmed pyrochlore or defect fluorite structures, while diffuse reflectance, X-ray absorption near edge structure and X-ray photoelectron spectroscopies indicate a predominantly U6+ oxidation state, even when Ca2+ was added to charge balance for U4+. The results demonstrate the potential of gadolinium zirconates as host materials for actinides.


Geosciences ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 275
Author(s):  
Madison Esposito ◽  
Kevin Souhrada ◽  
Erin Garland ◽  
Mary Kroll ◽  
Robert Bolen ◽  
...  

Micrometeorites (MMs) are small particles that account for most of the extraterrestrial material deposited on Earth. Synchrotron X-ray fluorescence and diffraction allowed for chemical and mineral characterization to distinguish MM from atmospheric particulate. The relative components of iron, nickel, and other elements were considered in the identification of ferrous MM while high amounts of titanium were considered an indication that the particles were of atmospheric origin. Out of 100 samples collected by high school students and teachers, eight were taken to a synchrotron for analysis. Of those eight, three exhibited extraterrestrial compositions. X-ray absorption near-edge structure analysis revealed that the same three samples contained sulfide, the main sulfur form constituent in MM. X-ray microdiffraction analysis showed the presence of the minerals pentlandite and forsterite. Collectively, these results support the extraterrestrial nature of the three particles.


1993 ◽  
Vol 37 ◽  
pp. 607-617 ◽  
Author(s):  
Glenn A. Waychunas ◽  
Gordon E. Brown

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.


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