Dielectric measurements on sol-gel derived titania films

Abstract

Alternating current (AC) impedance measurements were performed on 37 nm thick nanostructured sol-gel derived anatase titania films on ultrasonically cleaned (100) p-silicon substrates at temperatures T ranging from 100 K to 300 K over a frequency range between 20 Hz and 1 MHz. The frequency-dependent behavior of the AC conductivity sigma (ac)(f, T) obeys the universal power law, and the values of the effective hopping barrier and hopping distance were found to be 0.79 eV and 6.7 x 10(-11) m from an analysis due to the correlated barrier-hopping model. The dielectric relaxation was identified as a thermally activated non-Debye process involving an activation energy of 41.5 meV.