Cost reduction and uniformly distribution of carbon nanotubes are the two main topics in the field emission display application. Thermal chemical vapor deposition (T-CVD) is regarded as one of the best candidates of the growth methods due to the merits of simplicity and cost efficiency in the fabrication and large scalability. Besides, we also find titanium (Ti) layer can improve the uniformity and strengthen the adherence between the CNTs and substrate for CNTs’ growth. Therefore, co-deposited multilayer catalyst composed of Co and Ti on Al (Co-Ti/Al) is used in the T-CVD to grow pillar arrays of CNTs. It has been reported that the field emission can be effectively enhanced for the aligned CNTs as the field emitters when the ratio of distance between neighboring nanotubes (R) to the height of each individual CNT (H) is about 2. Although the pillar arrays of CNTs with different optimum R/H ratios to get best field emission characteristics were investigated by the different results have been reported. In this thesis, three different inter-pillar distances(80μm、150μm and 250μm) are designed to find the optimum R/H ratio of pillar arrays of CNTs by controlling the flow rate of carbon source and growth time precisely. The optimum R/H ratio is approaching to 2 when the inter-pillar distance is as larger as possible.CNT pillars probably behaves like an individual field emitter and has less field screening effect between pillars. The results show that when R/H ratios are 8, 4.7 and 3.2 for inter-pillar distance of 80μm、150μm and 250μm , respectively, ultra low turn-on field(1.78V/μm, 1.55V/μm and 1.53V/μm, respectively) is achieved and fluorescent uniformity can also be improved. Two-step method is used to grow CNT pillar array until with 80 μm in the height successfully. CNT pillar array synthesized with two-step method revealed a good field emission performance of an emission current density of 10mA/cm2 at the electric field of 0.64 V/μm, and field emission characteristics show a very ultra-low turn-on field of 0.1V/μm at an emission current density 10 μA/cm2 .As CNT pillar with one-step skill to two-step technique exhibit the IG/ID increases from 1.5 to 1.8 which confirms that the CNTs for the two-step one have a highly crystalline graphite structure as shown in TEM micrograph SEM show that thinner diameter about 24 nm is observed on the top of CNTs′ pillar. In addition to better crystallizing, the thinner diameter (i.e. high aspect ratio) also facilitate to the field emission characteristic. Plasma post-treatment is one of the best ways to improve the field emission properties and fluorescent uniformity. In this thesis, we propose O2 plus Cl2 plasma post-treatment to the pillar array of CNTs and the experimental results reveal that the improved emission properties can be achieved by optimizing the density of CNTs and the defects on the nanotubes under proper plasma treatment conditions. The turn-on field is reduced from 2.6 V/μm to 1.4 V/μm and the fluorescent uniformity is also improved when the plasma post-treatment time is 3 min for the O2 30sccm plus Cl2 10sccm. Finally, field emission triode is fabricated to reduce the operation voltage and improve emission uniformity by the beam spreading. The optimum parameters of the field emission trides are obtained according to the simulations, the gate-to-emitter length is 1 μm. The experimental results show that the driving voltage is as low as 17 V. In the future, this structure is promising for the applications in a planar backlight because of the large-area uniformity and simple fabrication process with low cost.