Fabrication Of Graphical Graphene And Carbon Nanotubes Hybrid Structure And Its Gas Sensing Property

Carbon nanotubes and graphene have attracted much attention due to their unique structures and excellent properties.New devices based on carbon nanotubes and graphene are emerging in endlessly,such as field-effect tubes,solar cells and gas sensors.In recent years,in order to combine their excellent properties,the researches on their hybrid materials have been developed and deepened.In this paper,we study the preparation process of graphical graphene and carbon nanotube hybrid structures connected by van der Waals force,and the gas sensing properties of the hybrid structure.In the process of preparing graphical graphene and carbon nanotube hybrid structure,we adjust the parameters of thermal CVD method to grow single layer graphene with low defects on graphical copper and nickel films whose pattern's minimum size is 10?m.Carbon nanotubes are assembled between graphene/metal electrodes by dielectric electrophoresis,and then the hybrid structures are examined by atomic force microscopy(AFM),scanning electron microscopy(SEM),and transmission electron microscopy(TEM).The DC resistance of the hybrid structures show that the distribution density between the electrodes and resistance of carbon nanotubes are controllable within the range of CNT solution concentration 0.005-2?g/ml and electrode gap 1-5?m,and the resistance of the hybrid structure can be predicted by the concentration of carbon nanotube solution and electrode gap.The gas sensitivity test results of the hybrid structure show that the hybrid structure prepared with pure carbon nanotubes have no obvious reaction with the dioxide and ammonia within 100 ppm.However,the hybrid structures prepared by carbon nanotubes modified with phosphomolybdic acid have a high gas response about 3.0% and 3.5% for nitrogen dioxide and ammonia at 5ppm,and the structures also have different response for nitrogen dioxide,ammonia,hydrogen,sulfur dioxide and carbon monoxide,which show that graphene and carbon nanotube hybrid structures have the potential to be designed and developed into excellent gas sensors.