Space-charge-limited conduction in vacuum-deposited PVDF films

Abstract

Current-voltage characteristics of poly(vinylidene fluoride) (PVDF) films fabricated on glass substrates by thermal evaporation technique in the metal-polymer-metal sandwich configuration were studied. The vacuum-deposited PVDF films were predominantly of α form. However, when subjected to high-voltage, short-duration singular pulse, it possibly resulted in mixed α + β form. The I-V curves of such films display the low-field ohmic region and the high-field square-law region. The current versus thickness curves in the square-law region and the transition voltage, Vtr, versus thickness curves indicate the conduction process to be space-charge-limited. The analyses of the current-voltage characteristics indicated the presence of uniformly distributed high-trapping carrier densities on the order of 1024 m-3 eV-1 with average activation energy of 0.263 eV.