An effect of electrode material on pinning layer characteristics and depolarization field in polymer ferroelectrics

An effect of electrode materials on the process of oriented film polarization of ferroelectric copolymers of vinylidenefluoride and tetrafuoroethylene has been studied. Electrodes of Al and Au were used, with their work function values being substantially different. Polarization was carried out by high-voltage impulse supply from which remnant polarization was estimated. Under the same conditions, the latter was shown to be higher in films with Au electrodes. The cause of this phenomenon was studied by the method of X-ray photoelectron spectroscopy, when chemical changes in the polymer surface were observed in situ during metal deposition on it. It was found that when Al was deposited, new functional groups were formed on the polymer surface. It was assumed that unlike in the case of Au, there was no complete compensation of the ferroelectric field, and the local field turned out to be lower than that determined by the external source. Published by AIP Publishing.