Hostname: page-component-586b7cd67f-t7fkt Total loading time: 0 Render date: 2024-11-28T12:57:39.690Z Has data issue: false hasContentIssue false

Influence of Metal Electrodes on the Ferroelectric Responses of Poly(vinylidene fluoride-trifluoroethylene) Copolymer Thin Films

Published online by Cambridge University Press:  11 February 2011

Feng Xia
Affiliation:
Department of Electrical Engineering andMaterials Research Institute, The Pennsylvania State University, University Park, PA 16802
Q. M. Zhang
Affiliation:
Department of Electrical Engineering andMaterials Research Institute, The Pennsylvania State University, University Park, PA 16802
Get access

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-trifluoroethylene) (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.

Type
Research Article
Copyright
Copyright © Materials Research Society 2003

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1. Bauer, S., J. Appl. Phys. 80, 5531 (1996).CrossRefGoogle Scholar
2. Wong, C. P., Polymers for Electronic and Photonic Applications (Academic Press, CA 1993).Google Scholar
3. Furukawa, T., Phase Transitions 18, 143 (1989).CrossRefGoogle Scholar
4. Zhang, Q. M., Xu, H. S., Fang, Fei, Cheng, Z.-Y, Xia, Feng, and Hou, Y. J. Appl. Phys. 89, 2613 (2001).CrossRefGoogle Scholar
5. Xia, Feng, Xu, H. S., Fang, Fei, Razavi, B., Cheng, Z.-Y, Lu, Yu, Xu, Baomin, and Zhang, Q. M., Appl. Phys. Lett. 78, 1122 (2001).CrossRefGoogle Scholar
6. Xia, Feng, Razavi, B., Xu, Haisheng, Cheng, Z.-Y, and Zhang, Q. M., J. Appl. Phys. 92, 3111 (2002).CrossRefGoogle Scholar
7. Zisman, W. A., Rev. Sci. Instrum. 3, 367 (1932).CrossRefGoogle Scholar
8. Michaelson, H. B., J. Appl. Phys. 48, 4729 (1977).CrossRefGoogle Scholar
9. Sze, S. M., Physics of Semiconductor Devices, 2nd ed. (Wiley, New York, 1981), p. 403.Google Scholar