Fabrication of metallic nanowires on a ferroelectric template via photochemical reaction

Fabrication of silver nanowires on a domain-patterned lithium niobate template by inducing a photochemical reaction in an aqueous solution is reported. Silver deposition occurs preferentially along the domain boundaries which separate antiparallel domains. The nanowires can reach lengths of hundreds of micrometres, and their location can be controlled by generating domain patterns of a desired configuration while their width depends on deposition conditions, such as temperature, solution concentration and ultraviolet (UV) light exposure time. The selective deposition process is explained by a combination of the inhomogeneous distribution of the electric field in the vicinity of the domain wall and the polarization screening mechanism of the template material. Controllable and selective deposition of metal species onto nanoscale domain-patterned ferroelectric templates may provide an alternative bottom-up route to lithographic fabrication methods. Miniaturization of electronic devices requires the development of structural elements of reduced dimensions. Metallic nanowires are attracting great interest due to their application as interconnecting components of nanoscale devices as well as chemical sensors and biological labels [1, 2]. Numerous techniques have been adopted for the growth of metal nanowires. Many of the top-down lithography-based methods provide high-precision positioning and size control, but are limited in downscaling the nanowire diameter below 50 nm [3, 4]. The bottom-up approaches allow fabrication of nanowires with much smaller diameters, but are time consuming, suffer from poor registration, and require special templates that, in turn, involve top-down processing [5]. In this paper, we present a liquid-phase processing method for the fabrication of silver nanowires on a domainpatterned ferroelectric template via a photochemical reaction. We demonstrate that the local reactivity on the ferroelectric surfaces depends not only on polarization but also on the intricate balance between polarization charges, adsorbed charges and defect states near the surface. It is shown that variations in the local surface electronic properties induced by the domain walls leads to preferential deposition of silver along the domain boundaries. As the domain walls in ferroelectrics can be as thin as several unit cells, this approach opens up the possibility of fabricating metallic wires of nanoscale