Influence of metal electrodes on the ferroelectric responses of poly(vinylidene fluoride-trifluoroethylene) copolymer thin films

Feng Xia, Qiming Zhang

    Research output: Contribution to journalConference articlepeer-review

    7 Scopus citations

    Abstract

    Ferroelectric polymer thin films have been investigated for applications such as sensors, MEMS, and memory devices, just name a few. In these thin film devices, it is anticipated that the interface effect will play an important role in determining the device performance. In this paper, we present the results of a recent study on the influence of metal electrodes on ferroelectric switching behavior of poly(vinylidene fluoride-trifluorocthylene) (P(VDF-TrFE)) polymer thin films. The results show that the influence of metal electrodes on the polarization response can be divided into two effects, the bulk effect and interface effect. The bulk effect manifests itself as the built-in bias field when metal electrodes with different work functions were used on the two surfaces of the P(VDF-TrFE) film. The interface effect is more complicated but is directly related to the metal work function. For a metal I/insulator (ferroelectric film)/metal II (MIM) sandwich structure in which the metal I and metal II possess different work functions, the low frequency polarization hysteresis loop shows asymmetric response (different switching fields). The polarization switching time also depends on whether the applied voltage is in parallel or anti-parallel to the built-in bias field. In the fast polarization switching process, it was observed that the interface effect plays a dominating role and the switching time is mainly limited by the charge injection from metal electrodes to the polymer film. For metal electrodes with higher work function, higher injection currents and hence faster polarization switching were observed. The results from I-V studies also show that the charge injection process is a Schottky type and the barrier height estimated from the temperature dependence of the I-V curves is consistent with the metal work functions used.

    Original languageEnglish (US)
    Pages (from-to)261-266
    Number of pages6
    JournalMaterials Research Society Symposium - Proceedings
    Volume734
    StatePublished - Jun 30 2003
    EventPolymer/Metal Interfaces and Defect Mediated Phenomena in Ordered Polymers - Boston, MA, United States
    Duration: Dec 2 2002Dec 6 2002

    All Science Journal Classification (ASJC) codes

    • Materials Science(all)
    • Condensed Matter Physics
    • Mechanics of Materials
    • Mechanical Engineering

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