Quantitative Analysis of Cu XANES Spectra Using Linear Combination Fitting of Binary Mixtures Simulated by FEFF9

Srisuda Rojsatien, Arun Mannodi-Kanakkithodi, Trumann Walker, Tara Nietzold, Eric Colegrove, Barry Lai, Zhonghou Cai, Martin Holt, Maria K.Y. Chan, Mariana I. Bertoni

Research output: Contribution to journalArticlepeer-review

1 Scopus Citations

Abstract

X-ray absorption near edge structure (XANES) is a powerful tool to probe the fingerprint of local structures, and when coupled with X-ray microscopy, the small spot size enables one to probe very specific regions of interest in a device or material, e.g. interfaces/bulk, different grains, good/bad electrical areas. In this work, we investigate the use of linear combination fitting (LCF) of XANES spectra for the particular case of Cu doping in CdTe. We show that the experimental data seem to be accurately represented by standards of Cu2Te and its substoichiometric counterpart, Cu1.43Te. We use Cu in CdTe as a case study to evaluate the accuracy of linear combination fitting using simulated standards, given that experimental standards for certain phases (e.g. Cu1.43Te) or defect structures (e.g. vacancies) cannot be readily obtained. We discuss how spectral features of the FEFF9-simulated standards, fitting ranges, and noise levels all dictate the accuracy of this type of analysis. We show that the greater the spectral difference between the two standards, the better the LCF is able to differentiate between the two structures and to tolerate experimental noise. Finally, we estimate the error of the fitted weights for different spectral features and noise levels and propose a framework to study local structures semi-quantitatively by using binary mixtures of FEFF9-simulated standards.

Original languageAmerican English
Article number110548
Number of pages9
JournalRadiation Physics and Chemistry
Volume202
DOIs
StatePublished - Jan 2023

Bibliographical note

Publisher Copyright:
© 2022

NREL Publication Number

  • NREL/JA-5K00-80528

Keywords

  • Cu in cdTe
  • FEFF9
  • Linear combination fitting (LCF)
  • Simulated XANES standards

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