Dielectric measurements on stearic acid/eicosylamine alternate layer Langmuir-Blodgett films incorporating CdS nanoparticles

Abstract

Langmuir-Blodgett deposition of 16 and 15 monolayers of stearic acid/eicosylamine has been accomplished on ultrasonically cleaned aluminized quartz substrate with 50 nm thick evaporated aluminium electrodes. Alternating current (AC) impedance measurements have been performed on with the aluminium (Al) top electrode in a sandwich configuration in the range of 100 Hz to 1 MHz and in the temperature ranging between 300 K <= T <= 360 K. The impedance data were fitted using an equivalent circuit which is mainly composed of resistors and constant phase elements (CPE). Complex impedance study highlighted the presence of a non-Debye type relaxation conduction: quantum mechanical tunnelling (QMT) through the barrier separating the localized sites and correlated barrier hopping.