Optical Properties of Nonstoichiometric Tantalum Oxide TaOx (x < 5/2) According to Spectral-Ellipsometry and Raman-Scattering Data

V. N. Kruchinin, V. A. Volodin, T. V. Perevalov, A. K. Gerasimova, V. Sh Aliev, V. A. Gritsenko

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)

Abstract

Optical properties of amorphous nonstoichiometric tantalum-oxide films of variable composition (TaOx, x = 1.94–2.51) in the spectral range of 1.12–4.96 eV, obtained by ion-beam sputtering-deposition of metallic tantalum at different partial oxygen pressures (0.53–9.09 × 10–3 Pa), have been investigated. It is shown by spectral ellipsometry that the character of dispersion of the absorption coefficient and refractive index in TaOx of variable composition suggests that light-absorbing films with dispersion similar to that in metals are formed at oxygen pressures in the growth chamber below 2.21 × 10–3 Pa, whereas transparent films with dielectric dispersion are formed at pressures above 2.81 × 10–3 Pa. According to the data of quantumchemical simulation, the absorption peak at a photon energy of 4.6 eV in TaOx observed in the absorptioncoefficient dispersion spectrum is due to oxygen vacancy. The peak in the Raman-scattering spectra of TaOx films with metallic dispersion at frequencies of 200–230 cm–1 is presumably related to tantalum nanoclusters.

Original languageEnglish
Pages (from-to)808-813
Number of pages6
JournalOptics and Spectroscopy (English translation of Optika i Spektroskopiya)
Volume124
Issue number6
DOIs
Publication statusPublished - 1 Jun 2018

Keywords

  • CHARGE-TRANSPORT
  • CRYSTALLINE

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