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Infrared study of nonstoichiometric anatase TiO2 nanopowders

Grujić-Brojčin M. (Center for Solid State Physics & New Materials, Instute of Physics, Belgrade)
Šćepanović M. (Center for Solid State Physics & New Materials, Instute of Physics, Belgrade)
Dohčević-Mitrović Z. (Center for Solid State Physics & New Materials, Instute of Physics, Belgrade)
Popović Z.V. (Center for Solid State Physics & New Materials, Instute of Physics, Belgrade)

The infrared (IR) reflectivity of laser synthesized TiO2 nanopowder in the anatase phase with a small deviation from stoichiometry is reported. The samples were characterized by SEM, XRD and BET measurements as well as Raman and photoluminescence spectroscopy. Analysis of the far IR reflectivity spectrum of the nanopowder reveals a presence of a plasmon mode. The charge carriers resulting from the lattice defects, mainly oxygen vacancies, are responsible for this mode. The dielectric function in a factorized form with a plasmon contribution is used to model the IR reflectivity spectrum and a good agreement between theoretical and experimental results has been found.

Keywords: anatase TiO2, nanopowder, plasmon-phonon coupling, infrared reflectivity