Controllable synthesis and tunable field-emission properties of tungsten oxide sub-micro fibers

A large amount of tungsten oxide (W18O49) sub-micro fiber arrays was prepared via a novel method on tungsten substrates, using tungsten trioxide powders as the source. Different growth densities and diameters of W18O49 sub-micro fibers were obtained when synthesized temperature was changed from 800 °C to 950 °C. The morphology and structure of the tungsten oxide sub-micro fibers were characterized by SEM, X-ray diffraction, and TEM. The average length of the resultant tungsten oxide sub-micro fibers is more than 5 μm, and their diameters are about several hundred nanometers. The synthesized fibers have a single-crystalline monoclinic structure with the growth direction of [010] and their growth mechanisms are discussed. Also, the relationships between the sub-micro fibers' field emission properties and their diameters and growth densities are investigated.

► Present a novel method for the synthesis of large-scale tungsten oxide (W18O49) sub-micro fiber arrays by chemical vapor deposition. ► The array density and diameter can be controlled by adjusting the process parameters. ► The field-emission properties of tungsten oxide sub-micro fiber arrays are tunable.