Schottky emission at the metal polymer interface and its effect on the polarization switching of ferroelectric poly(vinylidene fluoride-trifluoroethylene) copolymer thin films

In metal/insulator/metal sandwich structure, the interface between the metal and the insulator thin films plays significant roles in the functional performance of the thin films. In ferroelectric poly(vinylidene fluoride-trifluoroethylene) copylmer thin films metallized by different metals, it is found that the polarization switching is asymmetric due to the work function difference of the metal electrodes, and the degree of asymmetry increases with the increasing work function difference. For the samples with high work function metals as both or at least one of the electrodes, the polarization switching is much faster. The current-voltage curves at various temperatures indicated the interface-controlled asymmetric phenomena are mainly determined by the Schottky emission and charge injection at the metal/insulator polymer interface. (C) 2004 American Institute of Physics.