Controlled Synthesis of Nanowire Networks by Ion Track Template Electrodeposition

One-dimensional nanostructures have been studied intensively because of their interesting properties, which hold great promises for various applications [1]. However, to realize devices based on nanostructures, efficient methods that can translate a multitude of nanoscale components into micro/macroscale dimensions are needed. Controlled assembly is of particular importance for nanostructures used for catalysis, not only because loss of active surface area should be minimized, but also because the efficiency of a catalyst is related to the distribution of the material [2]. One of the most suitable techniques to achieve this aim is the direct synthesis of nanowire networks. These complex structures can be produced by templateless or templating techniques, the use of a template often allowing the better structural control [3]. However, none of the hard templates reported so far can precisely adjust the integration level and degree of connectivity. We recently developed a new approach to synthesize nanowire networks (NWNs) by a modified template electrodeposition method using track-etched polycarbonate membranes (Fig. 1). The membranes are irradiated at different angles in several steps with energetic heavy ions and subsequently etched in an aqueous NaOH solution. Filling the resulting 2-D or 3-D nanochannel network with a metal by electrodeposition leads to the formation of well-defined interconnected nanowires. The arising structure consists of numerous nanowires that are interconnected to a macroscopic network with dimensions up to several square centimetres and a typical height of 30 μm. After removing the template in an organic solvent,