Fabrication of Arrays of PZT Nanodots via Block Copolymer Self-Assembly

This article presents a simple methodology for the fabrication of two dimensional arrays of lead zirconate titanate (PZT) nanodots on n-doped Si substrates via the directed self-assembly of PS-b-PEO block copolymer templates. The approach produces highly ordered PZT nanodot patterns, with lateral widths and heights as small as 20 and 10 nm respectively, and a coverage density as high as ~ 68 × 10 nanodots cm. The existence of a pervoskite phase in the nanodots was confirmed by X-ray diffraction and X-ray photoelectron spectroscopy. The piezo-amplitude and ferroelectric domain response obtained from the nanodots, through piezoresponse force microscopy, confirmed the presence of ferroelectricity in the PZT arrays. Notably, PZT nanodots with a thickness ~ 10 nm, which is close to the critical size limit of PZT, showed ferroelectric behavior. The presence of a multi-a/c domain structure in the nanodots was attributed to their polycrystalline nature.