Nanomaterials (Nov 2021)

Evaluation of Optical and Acoustical Properties of Ba<sub>1−x</sub>Sr<sub>x</sub>TiO<sub>3</sub> Thin Film Material Library via Conjugation of Picosecond Laser Ultrasonics with X-ray Diffraction, Energy Dispersive Spectroscopy, Electron Probe Micro Analysis, Scanning Electron and Atomic Force Microscopies

  • Sathyan Sandeep,
  • Samuel Raetz,
  • Jerome Wolfman,
  • Beatrice Negulescu,
  • Guozhen Liu,
  • Jean-Louis Longuet,
  • Théo Thréard,
  • Vitalyi E. Gusev

DOI
https://doi.org/10.3390/nano11113131
Journal volume & issue
Vol. 11, no. 11
p. 3131

Abstract

Read online

Wide-range continuous spatial variation of the film composition in lateral compositionally graded epitaxial films requires the development of high throughput measurement techniques for their local and non-destructive characterization with the highest possible spatial resolution. Here we report on the first application of the picosecond laser ultrasonics (PLU) technique for the evaluation of acoustical and optical parameters of lateral compositionally graded film, the Ba1−xSrxTiO3 (0 ≤ x ≤ 1) material library. The film was not dedicatedly prepared for its opto-acousto-optic evaluation by PLU, exhibiting significant lateral variations in thickness and surface roughness. Therefore, the achieved measurements of the sound velocity and of the optical refractive index, and characterization of the surface roughness confirm the robustness of the PLU technique for thin film evaluation. We hope that the first measurements of the acoustical and optical properties of epitaxial grown Ba1−xSrxTiO3 (0 ≤ x ≤ 1) by PLU technique accomplished here provide the parameters required for more extended predictive design of the phononic, photonic and phoxonic mirrors and cavities with superior properties/functionalities for novel multifunctional nanodevices.

Keywords