Thermal Drawing of High-Density Macroscopic Arrays of Well-Ordered Sub-5-nm-Diameter Nanowires

We investigate the lower limit of nanowire diameters stably produced by the process of thermal fiber drawing and fiber tapering. A centimeter-scale macroscopic cylindrical preform containing the nanowire material in the core encased in a polymer scaffold cladding is thermally drawn in the viscous state to a fiber. By cascading several iterations of the process, continuous reduction of the diameter of an amorphous semiconducting chalcogenide glass is demonstrated. Starting from a 10-mm-diameter rod we thermally draw hundreds of meters of continuous sub-5-nm-diameter nanowires. Using this approach, we produce macroscopic lengths of high-density, well-ordered, globally oriented nanowire arrays.