On the degradation of conducting Langmuir-Blodgett films

Direct current through conducting Langmuir-Blodgett films was observed as a function of the applied voltage and alternating current as a function of frequency. In some cases voltage-current characteristics appeared to be quasi-ohmic but in other cases they exhibited tunnelling-like behaviour. This phenomenon was interpreted as being due to the progressive detachment of the film from the micro-electrodes, as confirmed by measurements of the conductivity as a function of time. This interpretation was also confirmed by estimating the tunnelling barrier parameters from voltage-current characteristics, by conductivity measurements before and after thermal treatment of the samples and by conductivity measurements of samples stored in air and under vacuum.