Template-Free Hydrothermal Synthesis of Single-Crystalline Barium Titanate and Strontium Titanate Nanowires

摘要

There has been considerable recent interest in the synthesis and characterization of one dimensional (1D) nanostruc-tures such as nanotubes, inorganic nanorods, and nano-wires.1D nanostructure systems offer the opportunity for investigating the influence of size and dimensionality of materials with respect to their collective optical, magnetic, and electronic properties. Understanding the behavior of ferroelectric materials at the nanoscale is important to the development of molecular electronics, in particular for random-access memory and logic circuitry. Most technologically important ferroelectrics are oxides with a perovskite structure, because that structure has a wide capacity characterized by a tolerance factor. These oxides, including BaTiO_3 and SrTiO_3, exhibit large nonlinear optical coefficients and large dielectric constants, which are responsible for their widespread applications in the manufacture of thermistors, multilayer capacitors, and electro-optical devices, electromechanical devices, transducers, capacitors, actuators, high-k dielectrics, dynamic random-access memory, and field-effect transistors. Because these effects are dependent on structure and finite size, considerable efforts have been expended in the controllable synthesis of crystalline materials and thin films of these ferroelectric oxides. Yun et al. investigated nanoscale ferroelectricity in BaTiO_3 nano-wires and showed nanoscale, nonvolatile memory applications.