Synthesizing tungsten oxide nanowires by a thermal evaporation method

Tungsten oxide W18O49 nanowires with diameters of 10–20nm were synthesized with high yield by thermal evaporation in a tube furnace. By heating tungsten trioxide powder at 900°C in vacuum (5×10−3torr), W18O49 nanowires with diameters of 10–20nm and lengths up to micrometers were produced with high yield on the Au-coated Si substrates located in the low temperature zone (550–600°C) of the furnace. The morphology, composition, and crystal structure of the nanowires were characterized by various methods. The conditions and the mechanism of W18O49 nanowire growth are discussed.