| When human build the civilization,they also bring inevitable damages to the ecology.Industrial emissions,car exhaust,home-use liquefied petroleum gas and natural gas,other toxic and flammable gas are not only seriously polluted the environment,but also endanger human health.Therefore,fabrication of gas sensors with high sensitivity and high selectivity for monitoring and alarming flammable and toxic gases is of great significance in theoretical research and practical application. Compared with traditional gas sensors,gas sensors based on individual one-dimensional nanostructures will exhibit even higher sensitivity and selectivity.Tungsten trioxide(WO3) one-dimensional nanostructures have been successfully synthesized in a simple hydrothermal method by using sodium tungstate as precursor under inorganic salts.The as-grown WO3 one-dimensional nanostructures were found to have uniform diameters with a crystalline hexagonal structure.The diameters and the lengths of the nanowires were about 30-75 nanometers and tens of micrometers, respectively.Then gas sensors based on individual WO3 were fabricated by deep ultraviolet submicron photolithography and coating technology. The test of gas sensing properties will be automatic controlled by using the concept of virtual instrument and the LabVIEW program.The electrical transport properties of WO3 one-dimensional nanostructures have been investigated.And then the effects of O2,NH3 and C2H5OH adsorption on the electrical transport of WO3 one-dimensional nanostructures under UV illumination at room temperature have also been investigated carefully.The experimental results show that WO3 one-dimensional nanostructures have highersensitivity and selectivity toNH3 molecules.We also discussed the gas sensing mechanism of one-dimensional nanostructures.In the end,the main problems encountered in experiments and the prospect of gas sensors based on one-dimensional nanostructures have been analysed and discussed.
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