Terahertz depolarization effects in colloidal TiO.sub.2./sub. films reveal particle morphology

0427099 - FZÚ 2015 RIV US eng J - Článek v odborném periodiku
Jensen, S.A. - Tielrooij, K.-J. - Hendry, E. - Bonn, M. - Rychetský, Ivan - Němec, Hynek
Terahertz depolarization effects in colloidal TiO₂ films reveal particle morphology.
Journal of Physical Chemistry C. Roč. 118, č. 2 (2014), s. 1191-1197. ISSN 1932-7447. E-ISSN 1932-7455
Grant CEP: GA ČR GA13-12386S; GA MŠMT LD12025
Institucionální podpora: RVO:68378271
Klíčová slova: time-resolved terahertz spectroscopy * TiO₂ nanoparticles * effective medium theory
Kód oboru RIV: BM - Fyzika pevných látek a magnetismus
Impakt faktor: 4.772, rok: 2014

The nature of electrical conductivity in films of TiO2 nanoparticles is of fundamental and practical interest. Their conductive properties depend strongly on their morphology and deviate greatly from the properties of the bulk material. We report ultrafast photoconductivity studies of films consisting of sintered TiO2 particles of very different sizes performed using time-resolved Terahertz spectroscopy. Identical photoconductivity spectra are observed for films of particles with diameters of tens and hundreds of nm, which demonstrates that the terahertz photoconductive response of colloidal TiO2 films is not affected by carrier backscattering at particle boundaries. Instead, depolarization fields resulting from the spatial inhomogeneities play the major role. Modelling of the influence of depolarization fields on the terahertz conductivity allows us to explain the measured data and gain insights into the morphology of the film.
Trvalý link: http://hdl.handle.net/11104/0232706