Controllable synthesis of Ni-catalyzed tetragonal tungsten nanowires via chemical vapor deposition

Tetragonal single-crystal tungsten nanowires were successfully synthesized by chemical vapor deposition (CVD) catalyzed by Ni particles. The influences of the catalysts, temperature and growth time on the formation of the nanowires were investigated. It was found that the tetragonal tungsten nanowires (WNWs) arrays were obtained by deterministic growth from the ordered Ni catalyst particles with one-to-one relation in size and position between the catalysts and nanowires. The large-scale tungsten nanowire arrays were synthesized at the low temperature of 950 °C. Samples were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). Increasing growth time at 950 °C, the tip of the WNWs changed from four (211) planes to four (110) planes. Good controls of the orientation and structure of WNWs arrays were important for adjusting their properties to satisfy different requirements of potential nanodevices.