Controllable Synthesis Of Carbon Nanomaterials And Field Emission Properties

Carbon nanomaterials with diverse structures, excellent physical and chemical properties, have attracted wide attention. Due to their unique structure and excellent performances, graphene and carbon nanotubes have emerged as hot directions of many research fields. One of the potential applications of graphene is in field emission source. To date, much work has been devoted to studying the field emission from the two materials, and the results have shown that graphene and carbon nanotubes are ideal cathode materials.In this paper, graphene with excellent field emission properties was prepared by different methods which took fully advantages of the material. Furthermore, the growth parameters of carbon nanotube were optimized and the field emission performances were enhanced. The relevantly main contents and conclusions were drawn as follows.The graphene emitters on micro-hole patterned stainless steel(SUS304) were prepared using electrophoresis method and the surface was treated by adhesive tape. The three-dimensional graphene emitters had lots of vertical aligned sharp edges. The field emission property was enhanced remarkably compared to that of graphene on flat substrates. The micro-hole patterned cathode provided lower turn-on and threshold fields and 10 times higher current density. This design may open a potential way to layered-nanomertial-based cold cathode.Carbon nanowalls(CNWs) were successfully fabricated on various substrates by radio frequency plasma-enhanced chemical vapor deposition. The influence of synthesis parameters on the field emission behaviors of CNWs was investigated in depth. The results showed that the morphology and microstructure of CNWs could be adjusted by growth parameters(temperature, pressure and gas flow rate), and CNWs with sharp edges displayed good field emission properties. The field emission characteristics of CNWs after stability test had no obvious deterioration, however, the morphology and microstructure of CNWs changed.Vertically carbon nanotube(CNT) arrays were successfully fabricated on different hexagon patterned Si substrates through radio frequency plasma-enhanced chemical vapor deposition. Different substrates, catalysts, intermediate buffer layers, H2/C2H2 gas flow rate ratio were used to investigate the effect on CNT growth and the field emission properties of CNT were optimized. The CNT emitters exhibited excellent field emission performance with high emission current density and good stability.