(A) study on the fabrication and optimization of carbon (nitride) nanotube-based field electron emitters

Abstract

Field emission of carbon nanotubes (CNT) has become a hot topic in recent years. It has the numerous perspective applications in novel nano electronic devices. One of the most attractive applications is the field emission display (FED). However, to realize the practical application there are several problem to be overcome. The cost of the device should be reasonable; lower turn-on field and higher emission current are desired; emission uniformity is another important target; in addition, the device should have stable performance in a reasonable lifetime. In this dissertation, improvements of field emission properties of carbon nanotubes by nitrogen doping have been study by experiment and theoretical calculation based on quantum mechanics. By using methane and hydrogen as precursors, patterned vertically aligned carbon nanotubes were synthesized by PECVD as the field emitters. Scanning electronic microscopy (SEM) and transmission electron microscopy (TEM) confirmed the structures of multi-walled carbon nanotube. Owning to the increase of the active emission sites where screening effect between neighboring nanotubes is minimized, field emission performance is expected to be improved by the patterning compared to CNT thin films without any patterning. By employing the patterned film of carbon nanotube as electron emitters, nitrogen doping into carbon nanotube effect were examined by both experiment and theory. TEM and Raman spectroscopy confirmed the intrinsic crystalline structure alteration induced by nitrogen incorporation. From TEM observation, bamboo-liked structure of carbon nitride nanotube $(CN_x)$ with defects was verified. On the other hand, carbon nanotube has the walls of graphite sheets paralleled to the axis of the tube. It was found that the structural modification by controlled amount of nitrogen-doping can tune the turn-on field and the emission current. Therefore, field emission performance of carbon nanotubes can be optimized by finding the...