Space charge investigation in beta -PVDF by thermally stimulated measurements

Thermally stimulated current measurements in beta -PVDF (polyvinylidene fluoride) films were carried out under an applied electric field. A strong peak was detected around 80 degrees C for E=100 kV/cm, and approximately at 100 degrees C for E=10 kV/cm. It was interpreted to be due to stored space charge thermally released, since the peak always disappeared in a second measurement. However, it was always present when consecutive measurements were carried out accompanied by an inversion of the applied field. It is suggested that the released charge was not swept away but remained trapped at surface traps. The authors obtained values of 1.0 and 1.4 eV, respectively, for the activation energies of the bulk and surface traps.<>