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An effect of the electrode material on space charge relaxation in ferroelectric copolymers of vinylidene fluoride.

An effect of the electrode material on space charge relaxation in ferroelectric copolymers of vinylidene fluoride.

Authors :
Kochervinskii, Valentin
Malyshkina, Inna
Pavlov, Alexey
Pakuro, Natalia
Bessonova, Natalia
Shmakova, Nina
Bedin, Sergey
Chubunova, Elena
Lebedinskii, Yuri
Source :
Journal of Applied Physics. 2015, Vol. 118 Issue 24, p244102-1-244102-9. 9p. 1 Chart, 9 Graphs.
Publication Year :
2015

Abstract

Processes of relaxation of space charges formed by impurities carriers in isotropic films of vinylidene fluoride and tetrafluoroethylene copolymers of the composition 71/29 and 94/6 were studied. Al and Au symmetric electrodes deposited by evaporation in vacuum have been used. In the case of Al electrodes at temperatures above 100 °C, giant low frequency dielectric dispersion was observed, while it is absent in films with Au electrodes. Causes of this phenomenon were studied by the X-ray photoelectron spectroscopy. It was shown that at Al deposition, new functional groups, such as Al-C, Al-F, and Al2O3, which are not characteristic of the copolymer film surface, formed. They were supposed to be traps for impurity carriers and because of this the electrode became partially blocked. This led to appearance of the giant electrode polarization on the metal-polymer boundary, which did not take place in the case of Au electrodes. Parameters of the Au4f line for the copolymer with different contents of fluorine atoms in the chain were analyzed. An increase in the number of these atoms was shown to result in the line shift to higher energies. This phenomenon was associated with an increase in the shift of the electron density from Au atoms to the F ones which has a high affinity to electrons. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
00218979
Volume :
118
Issue :
24
Database :
Academic Search Index
Journal :
Journal of Applied Physics
Publication Type :
Academic Journal
Accession number :
112036723
Full Text :
https://doi.org/10.1063/1.4938016