TY - JOUR
T1 - Unravelling local environments in mixed TiO2–SiO2 thin films by XPS and ab initio calculations
AU - Ondračka, Pavel
AU - Nečas, David
AU - Carette, Michèle
AU - Elisabeth, Stephane
AU - Holec, David
AU - Granier, Agnès
AU - Goullet, Antoine
AU - Zajíčková, Lenka
AU - Richard-Plouet, Mireille
N1 - Publisher Copyright: © 2020 Elsevier B.V.
PY - 2020/4/30
Y1 - 2020/4/30
N2 - Mixed Ti
xSi
1
−
xO
2 oxide can exhibit a partial phase separation of the TiO
2 and SiO
2 phases at the atomic level. The quantification of TiO
2–SiO
2 mixing in the amorphous material is complicated and was so far done mostly by infrared spectroscopy. We developed a new approach to the fitting of X-ray photoelectron spectroscopy data for the quantification of partial phase separation in amorphous Ti
xSi
1
−
xO
2 thin films deposited by plasma enhanced chemical vapour deposition. Several fitting constraints reducing the total number of degrees of freedom in the fits and thus the fit uncertainty were obtained by using core electron binding energies predicted by density functional theory calculations on Ti
xSi
1
−
xO
2 amorphous supercells. Consequently, a decomposition of the O 1s peak into TiO
2, SiO
2 and mixed components was possible. The component areas ratios were compared with the ratios predicted by older theoretical models based on the atomic environment statistics and we also developed several new models corresponding to more realistic atomic structure and partial mixing. Based on the comparison we conclude that the studied films are mostly disordered, with only a moderate phase separation.
AB - Mixed Ti
xSi
1
−
xO
2 oxide can exhibit a partial phase separation of the TiO
2 and SiO
2 phases at the atomic level. The quantification of TiO
2–SiO
2 mixing in the amorphous material is complicated and was so far done mostly by infrared spectroscopy. We developed a new approach to the fitting of X-ray photoelectron spectroscopy data for the quantification of partial phase separation in amorphous Ti
xSi
1
−
xO
2 thin films deposited by plasma enhanced chemical vapour deposition. Several fitting constraints reducing the total number of degrees of freedom in the fits and thus the fit uncertainty were obtained by using core electron binding energies predicted by density functional theory calculations on Ti
xSi
1
−
xO
2 amorphous supercells. Consequently, a decomposition of the O 1s peak into TiO
2, SiO
2 and mixed components was possible. The component areas ratios were compared with the ratios predicted by older theoretical models based on the atomic environment statistics and we also developed several new models corresponding to more realistic atomic structure and partial mixing. Based on the comparison we conclude that the studied films are mostly disordered, with only a moderate phase separation.
UR - http://www.scopus.com/inward/record.url?scp=85078889054&partnerID=8YFLogxK
U2 - 10.1016/j.apsusc.2019.145056
DO - 10.1016/j.apsusc.2019.145056
M3 - Article
SN - 0169-4332
VL - 510.2020
JO - Applied surface science
JF - Applied surface science
IS - 30 April
M1 - 145056
ER -