Synthesis,Characterization And Patterning Of Single-walled Carbon Nanotubes

Carbon nanotube(CNT)is a typical one-dimensional material,and a single-walled carbon nanotube(SWCNT)could be metallic or semiconducting according to its molecular structure.Taking the advantages of the small size,as well as the outstanding mechanical and electrical properties,CNT has a wide range of applications in many fields.At present,the research of carbon nanotubes is mainly focused on the synthesis,characterization and applications.In this thesis,a "surface trenching method" is put forward based on the practical requirement,which controllably and effectively reduces the array density without changing the growth condition.We have tried another two methods to reduce the array density,which are tunning the growth parameters and water introducing during normal growth condition.We found that the shortcomings of these two methods are the aging effect and the poor repeatability.Full-carbon devices,which are patterned and isolated by the "surface trenching method",have been tried to prepare.Taking into account of the efficiency of sample preparation and data analysis,we believe that scanning electron microscopy(SEM)has obvious advantages in the characterization of the morphology and the conductivity of nanomaterials.It would have great potential in the applications of the rapid and large-scale characterization.In this thesis,the working principle of the SEM is reviewed,and the information in the SEM images is classified in three catagories: the morphology,the material and the potential distribution.These three items are used to analyze the imaging mechanisms of the SWCNTs on the substrates of different conductivity.The SEM images under a variety of imaging parameters are presented,and the discrimination of conductivities is also discussed.Patterning is an essential process in the electronic application of the SWCNTs.In this thesis,the removal of carbon nanotubes is achieved by mechanical means,instead of the traditional reactive ion etching(RIE)method.On the one hand,the large-scale processing is achieved at the lowest cost.On the other hand,the substrate is well protected from the ion bombardment.Three methods have been developped: the white emulsion glue method,the rubbing method and the ultrasound method.The mechanical patterning of the SWCNTs are realized for both the random network on the silicon substrate and the array on the quartz substrate,and the accuracy is about 3 ?m.We also realized the patterning of the SWCNTs on the flexible substrate by using the white emulsion glue method.