Wafer-scale fabrication of ferroelectric oxide nanoshell tubes as well as ordered nanotube arrays have been accomplished using a simple and convenient fabrication method that allows full tailoring of tube dimensions as well as array pattern and size. Using different silicon and alumina templates, barium titanate and lead zirconate titanate tubes with diameters ranging from 50 nm up to several micrometers meter and lengths of more 100 μm have been fabricated. Ferroelectric switching of submicrometer tubes has been shown using piezoresponse scanning probe microscopy.

Lead zirconate titanate nanoislands were obtained by a self-patterning method making use of the instability of ultrathin films during high-temperature treatments. After high-temperature annealing, the as-deposited film breaks into islands with a narrow size distribution. The single-crystal nanoislands were studied by scanning and high-resolution transmission electron microscopy, atomic force microscopy, and x-ray diffraction. They show an epitaxial relationship with the Nb-doped (001) ${\mathrm{SrTiO}}_3$ substrate. The ferroelectric switching of several individual islands was investigated by piezoresponse force microscopy.

A quantitative high-resolution transmission electron microscopy study has been performed on tetragonal, single-crystalline $\mathrm{Pb}\left({\mathrm{Zr}}_{0.4}{\mathrm{Ti}}_{0.6}\right){\mathrm{O}}_3$ islands grown on Nb-doped $\mathrm{Sr}\mathrm{Ti}{\mathrm{O}}_3\left(001\right)$ substrates, revealing the strain fields of a 90° ferroelastic twin wall and the nearby interfacial dislocation. The twin wall, showing a width of $\sim 1.5\mathrm{nm}$ and compressive strain features, is elastically coupled to the tensile-type strain of an edge dislocation having an out-of-plane Burgers vector, indicating an intimate interaction of the strain fields of both crystallographic defects. The long-range strain field of the dislocation core imposes a potential barrier on the twin wall, limiting its translational mobility under an applied electric field. The substrate clamping in the epitaxial island further acts as a restoring force on the electric-field-induced wall movement. The ensemble of these electromechanical boundary conditions thus indicates that the ferroelastic twin wall in the island should be immobile upon external electric fields. A further discussion also suggests that this complex interplay of the substrate clamping and the interfacial dislocation should account for the reported low twin-wall mobility in continuous, epitaxial ferroelectric perovskite films under an electric field.