Growth of epitaxial tungsten oxide nanorods

Abstract

A simple vapour deposition technique was used to prepare WO 3 one-dimensional nanostructures. WO 3 is sublimated at a relatively low temperature (550 1C) in air at atmospheric pressure. The sublimated species are condensed on mica substrate at 500 1C. Single crystalline nanorods are grown in epitaxy on the mica surface with a growth axis along [0 1 0] directions and (0 0 1) plane parallel to the substrate. A growth process is proposed in which the formation of a onedimensional tetragonal tungsten bronze as precursor is the determining factor. r

Synthesis, Separation and Electrical Properties of WO3-xNanopowders via Partial Pressure High Energy Ball-Milling

“…The conductivity further increases and the value of activation energy of WO 2.7 NP is about 0.28(3) eV which corresponds to n-type semiconductor-like behavior. Results of WO 3 NPs conductivities and their interpretations as non-stoichiometric (process A) and hydrate (process B) originates from oxygen vacancies and are compatible with similar works that have been carried out in study of WO 3 thin films as a sensing material for detection of atmosphere pollutants [25][26][27][28][29][30][31].…”

“…The overall results of conductivity properties of the stable phases of processes A and B samples are grouped in Table II. Using milling, XRD, TEM and SAED analyses shows that there is an increase in the degree of lattice disorder and a decrease in the crystallite size, thereby reducing the symmetry of the unit cell until some fraction of the material becomes at NP. As reported previously [27][28][29], the mechanical activation resulted in the NP of minerals, development of large numbers of dislocation and their associated strain fields, which decrease the crystallite size and change the lattice parameters. These dislocations might lead to an overall decrease in long range lattice periodicity.…”

The nature of the air-cleaved mica surface

“…Nanowires of tungsten oxide may be grown on mica by subliming a WO3 thin film onto the substrate at atmospheric pressure, 30-40 % relative humidity and the relatively low temperature of 550 °C [215]. This temperature is far below the sublimation temperature of bulk WO3, and it is likely that water vapour is involved by converting the oxide to a hydroxide.…”

Influence of deposition conditions on the morphology and phase of tungsten oxide nanorods synthesized by thermal oxidation

“…It is also a promising material for applications in ion-lithium batteries [3], catalysts [4], photochromic materials [5] and solid lubricants [6]. Many different tungsten oxide nanostructures have been prepared such as thin film [5], nanorods [7,8], nanowires [9], and tree-structure [10]. Tungsten oxide nanorods are particularly interesting because they can exhibit very good field emission properties and thus could be candidate for application as the electron emission material in high-resolution flat displays, X-ray tubes, etc.…”