Tungsten Oxide

Nanostructures such as nanowires, nanorods, nanotubes of metal oxide semiconductor (MO S ) materials have recently attracted monumental interest in gas-sensing applications because of their excellent performances owing to their large surface to vol-ume ratio, lower electron recombination rate and high stability. Among various MO S  materials, tungsten trioxide (WO 3 ) is a highly promising candidate due to its fast response with high sensitivity toward NO x . Glancing angle depositio (GLAD) technique is a relatively new method for fabrication of well-ordered and sophisticated nanostructures i.e. nanorods, nanoblade and zigzag nanocolumns. It is a modified physical vapor deposition process, in which substrate surface is rotated and tilted to an angle greater than 80° with respect to the normal of substrate surface or less than 10°with respect to the direction of vapor flux. The vapor molecules directed to the substrate will experience shadowing and limited surface diffusion c...

Tungsten trioxide has shown good sensing properties towards various gases. Recently thin nanostructured WO3 films have been tested. Due to their large surface area to volume ratio they exhibit good sensitivity depending on the grain size. However in conventional WO3 thin films the average grain size exceeds the thickness of the surface space charge layer, so the electrical conduction is mainly controlled by the carriers transport across the grain boundaries. An alternative way seems to be in a monocrystalline material with nanometric dimensions.  Our objective is to fabricate nanosized tungsten oxide rods and to test their sensing properties under gas adsorption. We focus on the growth, the structure and the electrical properties of tungsten nanorods. The tungsten oxide nanorods were grown by vapour transport from a WO3 layer onto a substrate (Mica). The nanorods growth was controlled by the temperature gradient between the WO3 layer and the substrate. If you have ...

Nanostructures such as nanowires, nanorods, nanotubes of metal oxide semiconductor (MO S ) materials have recently attracted monumental interest in gas-sensing applications because of their excellent performances owing to their large surface to vol-ume ratio, lower electron recombination rate and high stability. Among various MO S  materials, tungsten oxide (WO 3 ) is a highly promising candidate due to its fast response with high sensitivity toward NO x . Glancing angle depositio (GLAD) technique is a relatively new method for fabrication of well-ordered and sophisticated nanostructures i.e. nanorods, nanoblade and zigzag nanocolumns. It is a modified physical vapor deposition process, in which substrate surface is rotated and tilted to an angle greater than 80° with respect to the normal of substrate surface or less than 10°with respect to the direction of vapor flux. The vapor molecules directed to the substrate will experience shadowing and limited surface diffusion condi...