TY - JOUR
T1 - Quantitative Analysis of Cu XANES Spectra Using Linear Combination Fitting of Binary Mixtures Simulated by FEFF9
AU - Rojsatien, Srisuda
AU - Mannodi-Kanakkithodi, Arun
AU - Walker, Trumann
AU - Nietzold, Tara
AU - Colegrove, Eric
AU - Lai, Barry
AU - Cai, Zhonghou
AU - Holt, Martin
AU - Chan, Maria K.Y.
AU - Bertoni, Mariana I.
N1 - Publisher Copyright:
© 2022
PY - 2023/1
Y1 - 2023/1
N2 - 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.
AB - 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.
KW - Cu in cdTe
KW - FEFF9
KW - Linear combination fitting (LCF)
KW - Simulated XANES standards
UR - http://www.scopus.com/inward/record.url?scp=85140071316&partnerID=8YFLogxK
U2 - 10.1016/j.radphyschem.2022.110548
DO - 10.1016/j.radphyschem.2022.110548
M3 - Article
AN - SCOPUS:85140071316
SN - 0969-806X
VL - 202
JO - Radiation Physics and Chemistry
JF - Radiation Physics and Chemistry
M1 - 110548
ER -