P(VDF-TrFE) nanofilm is a critical component in many organic electronics. Here we report the irreversible degradation of its ferroelectricity due to medium-energy electron irradiation (<10 keV), which is commonly found in device fabrication and characterization tools. The first-order electromechanical coupling in P(VDF-TrFE) was directly measured by atomic force microscopy to study the ferroelectricity switching property. Results showed that P(VDF-TrFE) films became non-ferroelectric after metal deposition in an electron-beam evaporator or after two minutes of observation under a scanning electron microscope. Lowering the electron energy slowed down the degradation process, but 500 eV electrons were still detrimental to the film. Irradiation is believed to transform the all-trans polar phase of P(VDF-TrFE) into a non-polar state, as revealed by infrared spectroscopy. On the other hand, controlled electron irradiation allows us to create patterns on the ferroelectric P(VDF-TrFE) thin films at submicron spatial resolution.
Bibliographical noteFunding Information:
The authors are truly grateful for the financial support from the Department of Mechanical Engineering and the College of Science and Engineering of the University of Minnesota. Research is also supported by NSF (ECCS-1150147). K. J. is thankful for the NSF IGERT grant (DGE-1069104). Parts of this work were carried out in the Characterization Facility, University of Minnesota, which receives partial support from NSF through the MRSEC program.
© The Royal Society of Chemistry 2015.