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.

Nanostructured carbon nitride films have peen synthesized by using a low-cost Penning discharge (PD) plasma-sputtering source. The influences of different working gas pressures on the surface morphologies, chemical compositions, bond structures, and mechanical properties of deposited carbon nitride thin films have been investigated using Scanning probe microscope (SPM), X-ray photoelectron spectroscopy (XPS) measurements, Raman spectroscopes, and nanoindentation measurements, respectively. SPM and XPS data indicate the variations of the root-mean-square roughness (R RMS ) of the samples surfaces from 7.5 nm, 11.4 nm, to 17.7 nm, and an increase of sp2 fraction inside the films from 22.8% to 26.9% with an up-shift of the deposition gas pressures. In contrast, the sp3 content decreases from 17.5% to 11.8%. The shifts of D and G peaks and variations of band intensity (ID/IG) have been observed in Raman spectra. The hardness of samples is reduced with increasing N2 partial pressure applied during film deposition.

The synthesis of boron nitride nanowires on silicon (Si) and nanorods on molybdenum (Mo) substrates at the same experimental conditions was composed. Fine tip nanowires with diameters around 50 nm were produced on Si substrates, whereas, nanorods with diameter around 100 nm were formed on Mo substrates. The change in length from 5 µm to 100 µm for nanowires and 0.2 µm to 0.8µm for nanorods following variation of substrate temperature were studied systematically.Scanning Electron Microscopy was used to analyze the surface images of BN nanowires and nanorods. Energy Dispersive X-Ray spectroscopy (EDS) was used to analyze boron and nitrogen concentration in the samples. The crystal structures of BN samples were investigated using Raman spectroscopy and x-ray diffraction. The experimental results showed that the nanorods are hexagonal mixed with cubic, whereas the nanowires are hexagonal.

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Diamond like carbon (DLC) films are synthesized on various substrates using a pulsed KrF excimer laser ablation deposition technique. Variations of laser power density, substrate temperature, angle and distance between the substrate and target yield different sizes of porous surfaces of DLC films. Microscope is used to examine the surfaces. Raman scattering is used to characterize the samples, and the typical G and D bands have been identified. Intensities and profiles of the G and D bands closely depend on laser power density. The relationship between the deposition rate and the power density is also studied.Keyword: pulsed laser beam, porous structure, diamond like carbon films Mater. Res. Soc. Symp. Proc. Vol. 954