Gas Sensing Properties Study Of Noble Metal Doped Tungsten Oxide Nanowires/Porous Silicon Sensors

Tungsten oxide is important and well-studied in materials science,particularly for sensor applications.In this research work,we consider the innovation of reducing size,composite structure and doping noble metal.Porous silicon has been widely used as a scaffold to synthesize nanowires and nanotubes.The porous silicon structure can be obtained from a simple electrochemical process.It is possible to tune pore diameters and pore spacing by adjusting parameters such as the type of electrolyte,the PH,and the applied voltage.In this work,we report an enhanced nitrogen dioxide?NO₂?gas sensor based on tungsten oxide?WO₃?nanowires/porous silicon?PS?decorated with gold?Au?nanoparticles.Au-loaded WO₃ nanowires with diameters of 10-25 nm and lengths of 300-500 nm have been fabricated by sputtering method on porous silicon substrate.The high-resolution transmission electron microscopy?HRTEM?micrographs show that Au nanoparticles were uniformly distributed on the surface of WO₃ nanowires.The effect of the Au nanoparticles on the NO₂-sensing performance of WO₃ nanowires/porous silicon was investigated over a low concentration range of 0.2-5 ppm of NO₂ at room temperature?25??.It was found that the 10 ? Au-loaded WO₃ nanowires/porous silicon based sensors possessed the highest gas response characterization.The underlying mechanism of the enhanced sensing properties of the Au-loaded WO₃ nanowires/porous silicon is also discussed.