Titanium-based nanoswords: Synthesis and characterization

Abstract

In this work, we report the discovery of a novel, titanium-based nanostructure, a nanosword, that may be quickly and easily synthesized in bulk using an induction heating system. The nanoswords are high-quality, single-crystalline structures that are synthesized without catalysts. The self- sourcing, vapor-solid synthesis technique presented is quick, with synthesis occurring in as low as five minutes, and simple, necessitating only a thin-film of evaporated titanium. Using scanning electron microscopy and transmission electron microscopy, the observed thicknesses of the nanoswords were 200-700 nm, widths were 20-60nm, and lengths were up to 5 mum. The ends of the nanoswords taper at an angle of 78-82deg to a sharp tip with radius of curvature as low as 2nm at an angle of 110- 114deg. Strong peaks of titanium and oxygen were observed in the energy dispersive x-ray spectroscopy. The reaction temperature was observed to influence the nanosword structure, with the best synthesis occurring at approximately 890degC. Three-point bend tests were performed using an atomic force microscope, and the average modulus of elasticity was measured to be 177 GPa. The nanosword structures, with their unique shape, repeatable crystallinity, and simple synthesis technique may be used as field emitters, nanobioprobes, nanoswitches, or for plasmonic applications, such as apertureless near-field scanning optical microscopy tips or localized surface enhanced Raman spectroscopy.