Fabrication of a Vertically Aligned Ferroelectric Perovskite Nanowire Array on Conducting Substrate

Abstract

A new fabrication process of a vertically aligned ferroelectric perovskite PbTiO3 nanowire array on Ti substrate is presented. Polycrystalline TiO2 nanotubes are first fabricated by anodic oxidation of Ti foil and then treated hydrothermally in a lead acetate solution to obtain single-crystalline nanowires. This nanotube-to-nanowire transformation on conducting substrate could be described by a swelling-and-rupture mechanism, in which individually well-developed nanotubes are swollen and broken along the friction planes because of difference in the directions of expansion force. Nanowires with a uniform diameter of ca. 40 nm and a length of 10 mu m show single-crystalline nature over the entire length of nanowires and ultrahigh density corresponding to ca. 0.22 Tb inch(-2). The ferroelectric property of individual PbTiO3 nanowires and whole area of nanowire arrays has been demonstrated by piezo-response force microscopy.