Growth of tungsten oxide nanowires using simple thermal heating

Tungsten oxide nanowires are grown directly on tungsten wires and plates using thermal heating in an acetylene and nitrogen mixture. By heating the tungsten in nitrogen ambient, single crystal tungsten oxide nanowires can be synthesized via a self-assembly mechanism. It was found that the yield can be significantly increased with the addition of acetylene, which also results in thinner nanowires, as compared to nanowires synthesized in an oxidizing ambient. The tungsten oxide nanowires are 5 to 15nm in diameter and hundreds of nanometers in length. In some cases, the use of acetylene and nitrogen process gas would result in tungsten oxide nanowires samples that appear visually transparent. Comparison of the growth using the acetylene/nitrogen or then air/nitrogen mixtures is carried out. A possible synthesis mechanism, taking into account the effect of hydrocarbon addition is proposed.