Study On Super-lattice Structure Of Graphene And Its Properties

As the first discovered two-dimensional crystal,graphene has outstanding electrical,mechanical,optical and thermal properties,which has wide application prospect in electronic devices,energy storage devices,sensors,composite materials etc.The actual existence of graphene is not an ideal two-dimensional structure,but there are different sizes of ripples.The ripple can not only avoid the dissociation of graphene due to the instability of thermodynamics,but also to a certain extent,it affects the electrical properties of graphene.Force Microscopy Atomic(AFM)is a kind of imaging tool based on the force of between the sample and the probe,which can be used to characterize the threedimensional shape of the surface of the sample,charge transfer,and the degree of reduction.In this paper,graphene is used as the object of study,and the high resolution of graphene is studied by atomic force microscopy.The specific content includes the following three aspects:1.Observing microstructure by Atomic Force Microscopy of graphene,by adjusting the force between the probe and the size,and found a periodic ripple in size of about 5 ?.The regularity of this kind of ripple on different substrates was observed.The reason of the formation of the ripple was analyzed by the first principle calculation results.The technology introduced additional electric field of graphene samples by Atomic Force Microscope tip charge injection,and found that the additional electric field also has a chance to trigger the 5 ? structure.2.Graphene has good flexibility,can copy the surface morphology accurately,and graphene is impermeable to water molecules,the behavior of water molecules between graphene and its influence on the properties of graphene can be studied.Confined water between graphene and the substrate according to the layered arrangement,layer thickness of about 3.7 ?.By controlling the change of environmental humidity,the morphology of the confined water between the graphene and the substrate can change with the change of humidity.3.The surface potential of graphene and substrate was measured by Kelvin probe force microscope.The confined water between graphene and the substrate has a positive effect on compensation of surface potential,which leads to some samples cannot observe 5 ? structure.