Heteroepitaxial growth of tungsten oxide films on sapphire for chemical gas sensors

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.…”

Deuterium retention in tungsten oxide under low energy plasma exposure

“…WO 3 films were prepared by oxidation of tungsten metal sheet (99.95% purity) of 0.2 mm in thickness ($0.5 Â 1 cm 2 in size) in air at 550°C for 1 h. Crystalline structure of the film is examined by Xray-diffraction (XRD) and ascribed to orthorhombic or monoclinic structure [4,5]. Rutherford backscattering spectroscopy (RBS) of 1.8 MeV He + and 2 MeV H + were used to obtain the film thickness and composition.…”

Oxygen-induced p(3×1) reconstruction of the W(100) surface

“…Tungsten trioxide WO 3 is the most stable oxide of tungsten and the final product of the oxidation of a tungsten surface. It is of particular interest due to its technological applications in electrochromic devices and chemiresistive gas sensors [9,10]. The WO 3 structure is based on corner-sharing WO 6 octahedra and resembles the cubic crystal structure of ReO 3 .…”