Two-dimensional self-patterning of PbTiO3 on a Nb–SrTiO3 (001) surface using atomic force microscope lithography and hydrothermal epitaxy

Atomic force microscope (AFM) lithography and hydrothermal epitaxy processes were used to resolve issues related to aligning ferroelectric micro- and nanosized cell arrays through a bottom-up approach. A Nb-doped SrTiO3 (100) surface was transformed in two dimensions by applying bias using a conductive AFM tip. The locally transformed areas were etched out with an acidic solution. It was found that the PbTiO3 crystal nucleated and grew on the artificially aligned grooves preferentially during a hydrothermal epitaxial process. The self-patterned PbTiO3 cell had excellent piezoresponse hysteresis with ferroelectric properties suitable for the fabrication of micro- and nanosized ferroelectric devices.