Nanostructured Tungsten Oxide Composite for High-Performance Gas Sensors.

Siyuan Chen,Ali Aldalbahi,Peter Feng

doi:10.3390/s151027035

Siyuan Chen, Ali Aldalbahi + Show 1 more

Open Access

https://doi.org/10.3390/s151027035

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Abstract

We report the results of composite tungsten oxide nanowires-based gas sensors. The morphologic surface, crystallographic structures, and chemical compositions of the obtained nanowires have been investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), and Raman scattering, respectively. The experimental measurements reveal that each wire consists of crystalline nanoparticles with an average diameter of less than 250 nm. By using the synthesized nanowires, highly sensitive prototypic gas sensors have been designed and fabricated. The dependence of the sensitivity of tungsten oxide nanowires to the methane and hydrogen gases as a function of time has been obtained. Various sensing parameters such as sensitivity, response time, stability, and repeatability were investigated in order to reveal the sensing ability.

Highlights

Oxide semiconductor films exhibit excellent properties for sensor devices [1,2,3,4,5]
Izadyar theoretically studied cyclic nanostructures of tungsten oxide as a sensing material for gas sensors [20]. Based on these achievements above, the present paper focuses on designing and developing simple, low-cost, room-temperature gas sensors based on tungsten oxide composite nanowires
The substrate temperature was controlled by adjusting the electrical current on the hot filament, which is different from our previous experiments where the substrate temperature is controlled by an additional heater under the substrate

Summary

Introduction

Oxide semiconductor films exhibit excellent properties for sensor devices [1,2,3,4,5]. Different metal oxide-based materials have different reaction (selectivity) activations to the target gases. They have a potential for detecting various gases. When considering the influence factors on gas-sensing properties of metal oxides, it is necessary to reveal their sensing mechanism. The fundamental mechanisms that cause a gas response are still controversial, but are thought to be essential to the trapping of electrons at adsorbed molecules that induces band bending, resulting in a change in conductivity. The reaction of species with reducing gases or a competitive adsorption and replacement of the adsorbed species by other molecules decreases and can reverse the band bending, resulting in the variation of conductivity [6,7]

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