By: Nguyen Van Hieu, Hoang Van Vuong, Nguyen Van Duy, Nguyen Duc Hoa.
Abstract: Controlling the proper geometrical morphology of metal oxide
nanowires (NWs) with large surface areas is important for enhancement of
gas-sensing performance through the improvement of sensing sites. In
this study, we synthesized geometrically controllable tungsten oxide NWs
for detection of NO2 at sub-ppm concentrations. Tungsten oxide NWs were
grown through the thermal evaporation method using WO3powders and W
foils as precursor and substrates, respectively. Effects of growth
conditions on the morphologies and gas-sensing properties of synthesized
NWs were investigated. Results revealed that the as-obtained NWs
possessed a cross-section of polygonal shapes, and their diameters
increased as the growth temperature increased from 950 °C to 1000 °C.
However, the NWs formed bundles and generated porous structures as the
growth temperature increased up to 1050 °C. The comparative NO2
gas-sensing properties of tungsten oxide NWs synthesized at different
growth temperatures indicated that the NWs synthesized at 1050 °C
exhibited relatively good NO2 sensing performance at the sub-ppm level
because of the formation of porous NW structures. This phenomenon
suggested that porous tungsten oxide NWs are effective for highly
sensitive NO2 gas sensor applications....Full paper
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