Since its discovery in 1991, the carbon nanotubes(CNTs) has attracted much attention all over the world and several methods have been developed to synthesize CNTs (arc discharge, laser ablation, chemical vapor deposition methods). As for electronic properties, calculations show that they may be metal or semimetal depending on their diameters and chiralities. According to theoretical calculations, CNTs have many unique properties such as high mechanical strength, capillary properties, and remarkable electronic conductivity, all of which suggest a wide range of potential applications in the future. So many applications of CNTs have been proposed, for example, electron emitters, probes in scanning probe microscopy, single electron transistors, quantum wires, and electrochmical probes, hydrogen storage, electrochemical supercapacitor, an anode for lithium ion batteries.
Recently, large-scale highly orientated CNTs have been synthesized by using thermal decomposition of hydrocarbon on various substrates, and sublimation decomposition of silicon carbide. However, the synthesis temperature of these methods is all above 700℃, which are unsuitable for the fabrication process of electronic devices because most electronic connections are made of aluminum whose melting point is below 700℃. In addition, CNTs' electronic property as a tip for field emission display is not good because of their high density.
Therefore their growth temperature has to be decreased and their density has to be controlled for high electric field emission property. In this study CNTs' growth temperature was decreased below 600℃ by using MPECVD method and their density was controlled by plasma etching and variation of plasma density distribution during growth of CNTs. Especially by plasma etching and variation of plasma distribution during growth of CNTs, their field emission property was improved by lower density and increase of CNTs' defects and they could be used for commercial FED tips because of their high current density.
