Defects exist in almost all materials and defect engineering at the atomic level is part of modern semiconductor technology. Defects and their long-range strain fields can have a negative impact on the host materials. In materials with confined dimensions, the influence of defects can be even more pronounced due to the enhanced relative volume of the 'defective' regions. Here we report the dislocation-induced polarization instability of (001)-oriented Pb(Zr(0.52)Ti(0.48))O(3) (PZT) nanoislands, with an average height of approximately 9 nm, grown on compressive perovskite substrates. Using quantitative high-resolution electron microscopy, we visualize the strain fields of edge-type misfit dislocations, extending predominantly into a PZT region with a height of approximately 4 nm and width of approximately 8 nm. The lattice within this region deviates from the regular crystal structure. Piezoresponse force microscopy indicates that such PZT nanoislands do not show ferroelectricity. Our results suggest that misfit engineering is indispensable for obtaining nanostructured ferroelectrics with stable polarization.

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 m 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) SrTiO3 substrate. The ferroelectric switching of several individual islands was investigated by piezoresponse force microscopy.

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