The elastic component of anisotropic strain dominates the observed shift in the F2g Raman mode of anelastic ceria thin films

Daniel Freidzon, Olga Kraynis, Ellen Wachtel, Igor Lubomirsky, Tsachi Livneh

Research output: Contribution to journalArticlepeer-review

Abstract

Raman spectroscopy is applied for non-destructive characterization of strain in crystalline thin films. The analysis makes use of the numerical value of the mode Grüneisen parameter γ, which relates the fractional change in the frequency of a Raman-active vibrational mode and the strain-induced fractional change in the unit cell volume. When in-plane, compressive biaxial strain in aliovalent doped CeO2-films is relieved by partial substrate removal, the films exhibit values of γ for the F2g vibrational mode which are ∼30% of the literature values for bulk ceramics under isostatic stress. This discrepancy has been attributed to a negative contribution from the anelastic (time-dependent) mechanical properties of aliovalent-doped ceria. Here we propose a way to “separate” anelastic and elastic contributions to the F2g mode Grüneisen parameter. Mechanically elastic yttria (Y2O3) films on Ti/SiO2/Si substrate serve as “control”. The values of γ calculated from the change in frequency of the ∼375 cm−1 F2g Raman-active mode are close to the literature values for bulk yttria under isostatic stress. This work should serve to provide a protocol for characterization of selective sensitivity to different strain components of doped ceria thin films.

Original languageEnglish
Pages (from-to)30563-30571
Number of pages9
JournalPhysical Chemistry Chemical Physics
Volume25
Issue number44
DOIs
StatePublished - 15 Nov 2023
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2023 The Royal Society of Chemistry.

Funding

This work was supported by the PAZY foundation grant #2018/57. This work made possible in part by the generosity of the Harold Perlman Family and was in part supported by the Minerva Center for Self-Repairing Systems for Energy & Sustainability.

FundersFunder number
Minerva Center for Self-Repairing Systems for Energy & Sustainability

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