Ferroelectric PbTiO₃ nanostructures onto Si-based substrates with size and shape control

A bottom-up approach based on the use of a microemulsion-assisted chemical solution deposition method, previously developed for the fabrication of PbTiO₃ nanostructures onto single crystal SrTiO₃ substrates, is used here on polycrystalline Pt/Si-based substrates, aiming at their integration with the current microelectronics technology. This bottom-up approach not only does not produce any damage to the nanostructures, thus not affecting noticeably their ferroelectric properties, but also solves some of the problems associated to those approaches that use the microstructural instability of ultrathin films, where islands with different shapes and sizes (single or bimodal log-normal distributions) are obtained. In this case, normal (Gaussian) size distributions are obtained, with average lateral sizes of ~70 nm, weakly depending on the solution concentration. These results show that the growth process of the nanoparticles takes place independently from one another inside the isolated micelles of the precursor solution, whose shape and size distribution therefore control effectively those of the PbTiO₃ nanostructures.