Structures and local polarized domains of ferroelectric organic films studied by atomic force microscopy

We have investigated the surface structures and the local polarized domains of the copolymer thin films of vinylidene fluoride and trifluoroethylene (P(VDF/TrFE)) by atomic force microscopy (AFM). AFM observation revealed that the films consisted of 'rod-like' grains and that the surface morphology depended strongly on the annealing condition. We also observed that pairs of 'rod-like' grains were gradually formed depending on the length of the annealing time. The local polarized domains were fabricated by applying a high electric field to the film with a conducting AFM tip. The piezoelectric response of the film was detected using the tip with an oscillating electric field and imaged with the topographic images taken simultaneously. The X-ray profile suggested that the thin films had a β-type crystalline structure.