Tungsten oxide nanorods were prepared from
W2N film by a simple
annealing method. W2N
film was deposited on a Si(100) substrate by chemical vapour deposition (CVD) at
450 °C, and then heating
of the film at 600–700 °C
produces a high density of tungsten oxide nanorods. The morphology, structure, composition
and chemical binding states of the prepared nanorods were characterized by scanning electron
microscopy (SEM), x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), energy
dispersive x-ray analysis (EDX) and transmission electron microscopy (TEM) measurements.
XRD and TEM analysis showed that the grown nanorods were single-crystalline
W18O49. According to
XPS analysis, the W18O49
nanorods contained ∼62%
of W6+,
∼28% of
W5+,
and ∼10%
of W4+. Field-emission measurements showed a low turn-on field of
9.5 V µm−1 for
the W18O49
nanorods, indicating that they can be used as potential field emitters. Also, a synthesis reaction
mechanism based on thermodynamics is proposed for the growth of tungsten oxide nanorods from
W2N.