Synthesis and characterization of tungsten oxide nanorods from chemical vapor deposition-grown tungsten film by low-temperature thermal annealing

摘要

A simple thermal annealing was performed to prepare tungsten oxide nanorods directly from tungsten (W) film. The W film was deposited on Si(100) substrate by chemical vapor deposition (CVD) at 450 ℃ using W(C0)_6. A high density of tungsten oxide nanorods was produced by heating of the W film at 600-700 ℃. 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), and transmission electron microscopy (TEM) analysis. XRD and TEM results showed that the grown nanorods were single-crystalline W_(18)O_(49). According to XPS analysis, the W_(18)O_(49) nanorods contained -55.69% W~(6+), -32.28% W~(5+), and -12.03% W~(4+). The growth mechanism based on thermodynamics is discussed for the growth of tungsten oxide nanorods from W film.