Controlled growth and characterization of tungsten oxide nanowires using thermal evaporation of WO3 powder

Tungsten oxide (WO3) nanowires were prepared on a tungsten (W) substrate by thermal evaporation of WO3 powder at elevated temperature in a tube furnace. The morphology, structure, composition, and chemical state of the prepared nanowires were characterized by SEM, EDX, TEM, XRD, Raman spectroscopic, and XPS measurements. The nanowires grown using WO3 powder were found to have uniform morphology with a high density and a crystalline structure consistent with monoclinic WO3. The field-emission measurements showed that the prepared nanowires have a turn-on field of 4.8 V/mu m. The role Of WO3 powder in the growth of high-density nanowires has been discussed by comparing the above results with those of nanowires grown without using WO3 powder and also on a different substrate. Also, the effects of growth temperature on the chemical binding states and product morphology of the nanowires were investigated.