Charge storage mechanism in vacuum deposited PVF films

摘要

Thermally stimulated discharge current (TSD) behavior of vacuum deposited polyvinyl fluoride (PVF) films has been studied as a function of various polarization parameters such as field (1.0 × 103–14.0 × 103 V/cm), temperature (313–453 K), time (3.6 × 103–6.0 × 103 sec), electrode work function (copper, silver, aluminum and indium) and thickness (2000–10000 Å). In a field dependent case the TSD spectra of PVF films show a single relaxation peak centered around 430 ± 1 K. The peak current, charge, peak position and activation energy associated with the peak depend strongly on the polarization parameters. The mechanism of origin of the relaxation peak has been attributed to the space charge polarization where the charge carriers injected at the electrode-polymer interface barrier are displaced at macroscopic distances and get subsequently trapped at trapping levels that are distributed in their activation energies and relaxation times.