Ambient Pressure Synthesis of Nanostructured Tungsten Oxide Crystalline Films

Abstract

We report the results of the ambient pressure synthesis of tungsten oxide nanowires and nanoparticles on AlN substrates using the hot filament CVD techniques. The morphologic surface, crystallographic structures, chemical compositions, and bond structures of the obtained samples have been investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), and Raman scattering, respectively. Different morphologies were observed for different substrate temperatures, but otherwise identical growth conditions. The experimental measurements reveal the evolutions of the crystalline states and bond structures following the substrate temperatures. Besides, different substrate materials also affected the tungsten oxide nanostructures. Bundles of wire-type tungsten oxide nanowires with a length of up to 5 mm were obtained on Al 2 O 3 substrate. Furthermore, the sensitive properties of the super long nanowires to the gas and different temperature were investigated. The dependence of the sensitivity of tungsten oxide nanowires to the methane as a function of the time was obtained. The sensitive properties of the tungsten oxide nanowires have almost linear relationship with the temperature.

Bandgap-Tuned 2D Boron Nitride/Tungsten Nitride Nanocomposites for Development of High-Performance Deep Ultraviolet Selective Photodetectors

“…The band at 200-300 cm −1 has a stronger Raman signal than that one at ~800 cm −1 . This is different from that of WO [22][23][24]. In general, tungsten nitride forms together with little tungsten oxide.…”

Effect of Tungsten Oxide Nanostructures on Sensitivity and Selectivity of Pollution Gases

“…However, no similar phenomenon is observed from the stretching modes. Previous work indicated that spectral lines were blue shifts following an increase in the substrate temperature during synthesizing [ 43 ]. In general, the blue shift in the Raman peaks should result from the change in crystal symmetry.…”

“…This simple and cost-effective synthesis technique was different from the method used in our previous work [ 40 , 41 , 42 , 43 ]. In the present work, the tungsten oxide composites were synthesized using a simple hot-filament CVD technique where the tungsten filament itself acted as a precursor for tungsten oxide, without using any catalyst or other tungsten-containing compound precursors.…”

Metal–organic decomposition synthesis of tungsten oxide nanoparticles and evaluation of visible-light-driven photocatalytic ability

“…19) Such phase transition, stoichiometric change, and oxidation-reduction reactions were reported previously. 20) These factors enhance solid chemical reactions and affect the synthesized nanoparticles and photocatalytic abilitiy. 19) To investigate the baking temperature dependence of synthesized nanoparticles on the crystal structure, we measured the XRD spectra of the samples.…”