Research On Field Emission Characteristics Of Single Walled Carbon Nanotubes And Zinc Oxide Nanowires

The present development of field emission characteristics of single walled carbon nanotubes(SWNTs) and zinc oxide nanowires at home and abroad was introduced, their field emission characteristics were studied with field emission microscope(FEM) and field ion microscope(FIM). Several problems about electric field in the field emission have been simulated with finite element method.Carbon nanotubes were regarded as one of the most outstanding field emission materials, but up to now the viewpoints on their field emission mechanism were different. SWNTs' structure is simple and the relationship of their structure and properties is direct. Research on their field emission characteristics with FEM and FIM is helpful to the understanding of their field emission mechanism and the relationship of their end structures with their field emission properties. Two methods of assembling SWNTs on tungsten tips such as physical method and chemical method were provided. The influence of different assembling methods on their field emission characteristics was analyzed. The relationship of their field emission image and field ion image was discussed. The field emission current fluctuation of SWNTs and its influential factors were also included in the thesis.Zinc oxide is a kind of excellent multi-functional semiconductor materials, zinc oxide nanowires have a lot of new optical and electronic characteristics, and one of its functions in the electronic frontier is worked as field emission electron source. The field emission characteristics of zinc oxide nanowires grown on the tungsten tips and the influence of heat treatment on their field emission properties were discussed in the thesis.Finite element method is an excellent numerical computation method. Several problems about the electric field in the field emission have been simulated with the finite element method.