| Nanomaterials and nanostructures have received great interests due to their peculiar and fascinating properties, superior to their bulk counterparts for applications. To date, the most possible practicality and marketability of the nanomaterials are the field emission display manufacture that utilizes the excellent field emission property of some nanomaterials and nanostructures. The cold cathode is one of the focus of the nanomaterials study even the whole nanotechnology research. Therefore, supported by the National Natural Science Foundation (Nos. 69925409, 10374027) and Shanghai science and technology item (No. 015211066) the preparation processes, microstructures, and electron field emission properties of carbon nanotube films, silicon nanocrystallite films, and zinc oxide nanostructures were investigated in this work. Main concludes and innovative results are listed as follow:1) Large-scaled multi-walled carbon nanotube (MWNT) films have been fabricated using screen-printing and electrophoresis deposition technique. The effects of annealing and hydrogen plasma (HP) treatment on MWNT films were investigated, it is found that annealing and hydrogen plasma treatment could greatly improve the field emission properties of MWNT films. For the HP treated MWNT films, the low turn-on field of 1.1V/um, threshold field of 5.3 v/ u m, and high emission site density of 105/cm2 have been achieved respectively. A novel structure of HP treated MWNT was found, and the surface morphology and microstructure features of the films before and after HP treatment were investigated in terms of SEM, TEM, HRTEM, Raman, XPS and FTIR. The conversion mechanism of the HP treated carbon nanotube structures and the origin for the change of the electronic and field emission characteristics of the MWNT films were discussed.2) The effects of grinding for different time in a vibrating mill on the mixture of Fe nanopowder and multi-walled carbon nanotubes were studied. The morphology and structures of the ground MWNTs were investigated using SEM and TEM. The results show that a part of closed ends of the tubes were broken and graphite layer of some nanotubes were tortured while ground for 8h. The field emission measurement results indicated theimprovement of field emission properties of the ground MWNT films. The turn-on field of 2.1 V/ u m, threshold field of 3.6 V/ u m, and emission site density of 104/cm2 were obtained.3) Homogeneous MWNT films have been fabricated by a spin-coating method using the soluble octadecylamine (ODA) modified multi-wall carbon nanotubes. The characterization, by means of electron microscopy and micro-Raman spectroscopy, shows that the surfaces of MWNTs-ODA with HP treatment are covered by the carbon nanoparticles. The field emission tests indicate that the treated MWNTs-ODA film has low turn-on field of 0.5 V/ u m , threshold field of 3.2 V/um, and high emission site density of 103~104/cm2.4) Compact aligned, (100)-orientated silicon nanocrystallite films were fabricated by the anodic etching method. Field emission measurements of the films with different grain sizes and thicknesses were performed before and after HP treatments respectively. The experimental results demonstrated that the SiNC films with lower turn-on field and threshold field could be used for flat panel displays.5) Tetrapod-like and wire-like ZnO nanostructures were successfully synthesized by a thermal evaporation method. In our method, no metal catalyst, graphite additive, and vacuum condition were used. It could be important for large-scale industrialization. The field emission characteristics of the ZnO nanostructures were studied for the first time. The turn-on field is found to be as low as 1.8 V/ u m, equivalent to that of MWNTs. Our results demonstrated that tetrapod-like ZnO nanostructures have potential application in the field of vacuum electron devices.6) ZnO nanorods, nanobelts, and nanopillars were prepared on the metal-filled porous silicon and nanocrystallite silicon by a vapor phase transport m...
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