Nanostructure of photocatalytic TiO 2 films sputtered at temperatures below 200 °C

J. Šícha, J. Musil, M. Meissner, R. Čerstvý

Research output: Contribution to journalArticle

53 Citations (Scopus)

Abstract

The article reports on correlations between the process parameters of reactive pulsed dc magnetron sputtering, physical properties and the photocatalytic activity (PCA) of TiO 2 films sputtered at substrate surface temperature T surf ≤ 180 °C. Films were deposited using a dual magnetron system equipped with Ti (Ø50 mm) targets in Ar + O 2 atmosphere in oxide mode of sputtering. The TiO 2 films with highly photoactive anatase phase were prepared without a post-deposition thermal annealing. The decomposition rate of the acid orange 7 (AO7) solution during the photoactivation of the TiO 2 film with UV light was used for characterization of the film PCA. It was found that (i) the partial pressure of oxygen p O 2 and the total sputtering gas pressure p T are the key deposition parameters influencing the TiO 2 film phase composition that directly affects its PCA, (ii) the structure of sputtered TiO 2 films varies along the growth direction from the film/substrate interface to the film surface, (iii) ∼500 nm thick anatase TiO 2 films with high PCA were prepared and (iv) the structure of sputtered TiO 2 films is not affected by the substrate surface temperature T surf when T surf < 180 °C. The interruption of the sputtering process and deposition in long (tens of minutes) pulses alternating with cooling pauses has no effect on the structure and the PCA of TiO 2 films and results in a decrease of maximum value of T surf necessary for the creation of nanocrystalline nc-TiO 2 film. It was demonstrated that crystalline TiO 2 films with high PCA can be sputtered at T surf ≤ 130 °C. Based on obtained results a phase zone model of TiO 2 films was developed.

Original languageEnglish
Pages (from-to)3793-3800
Number of pages8
JournalApplied Surface Science
Volume254
Issue number13
DOIs
Publication statusPublished - 30 Apr 2008

Keywords

  • Anatase
  • Dual magnetron
  • Low-temperature sputtering
  • Structure
  • TiO film
  • UV induced photocatalysis

ASJC Scopus subject areas

  • Surfaces, Coatings and Films

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