Study On Preparation And Gas-sensing Properties Of Aligned Tungsten Oxide Nanowire Arrays

As we all know,sensor technology is one of the core technology of the Internet of Things.The future world would covered by various sensors which will collect all kinds of data on the earth.Meanwhile,the deterioration of the ecological environment is the urgent problem in today's world,and with sensor technology the Internet of Things would be successes in deal with that problem.NO₂ is one of the main air pollutants.Gas sensor based on tungsten oxide has exhibited remarkable sensing performance to NO₂ gas.In this paper,aligned tungsten oxide nanowire arrays have been studied in gas sensor applications which including the preparation of aligned tungsten oxide nanowires array and the evaluation gas sensitive performance.In this paper,the aligned arrays of tungsten oxide nanowires were formed directly via a novel route of in situ thermal oxidation of sputtered W film on the substrate.The well-developed nanowires have diameter of 10-20 nm and show roughly aligned morphology.The effects of different experimental factors on the products have been studied,and standard range of each parameter for successful preparation of tungsten oxide nanowires has been concluded.Besides,it is found that the duration of oxygen exposure during thermal annealing plays a crucial role to harvest different phase of tungsten oxide nanowires.And the explanation of growth mechanism of tungsten oxide nanowires has been innovative proposed which combined with our experimental results and reference.The NO₂-sensing properties of aligned tungsten oxide nanowire arrays sensor were evaluated at 50? up to 200 ? over NO₂ concentration ranging from 0.25 to 5 ppm.The results indicate that the tungsten oxide nanowire sensor exhibits good NO₂-sensing performances: 150 ? of optimal operating temperature;response is about 4.4 to 1 ppm NO₂ gas at that temperature;response and recovery time is about 78 and 32 s;good performances of stability and selectivity.Especially perfect fast responserecovery characteristics due to its specific aligned arrays structure.Besides,the rapid annealing effects on its gas sensitive performance also have been studied.Proper annealing conditions can slightly improve its performance.