Fabrication of Field Emission Lamps Cathode Wires and Analysis of Their Failure

• Main Authors: Jiang, Jhih-Cheng, 江智程
• Other Authors: Liu Yih-Ming
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/43936345596128462782

碩士 === 國防大學理工學院 === 材料科學與工程碩士班 === 101 === Carbon nano-coils grown with thermal chemical vapor deposition (TCVD) were used to fabricate the cathode filaments of field emission bulbs (FEBs) in this thesis. The first part of this thesis focuses mainly on how to increase the field emission efficiency of the cathode filaments. By increasing the process temperature and adjusting the flow rate of acetylene to increase the crystallinity of grown carbon nano-coils, the field emission properties of the filament cathodes can be enhanced. Moreover, the post-treatment of the cathode filaments with nitrogen gas at 200℃ was studied to evaluate influence of the post-treatment parameters on CNCs. The nitrogen post-treatment parameters were optimized to increase the efficiency and lifetime of the filament cathodes of FEBs. In the second part of this thesis, production scale-up of the CNC cathode filaments was studied. Due to the size limitation of our existing three-inch diameter TCVD furnace, its production capacity is 6 cathode filaments per batch. To achieve the objective for present FEL study and future commercialization demand, we have shifted the production of CNC cathode filaments from three-inch diameter TCVD furnace to a six-inch diameter one. The optimal process parameters for three-inch diameter TCVD were dedicated tuned for the six-inch diameter TCVD furnace to raise the yield from 6 cathode filaments per batch to 28 filaments per batch. The damage of cathode filaments in the process of researching and testing FEBs was evaluated in the last part of this thesis. The result indicates that when the vacuum was not high enough or outgassing happened from anode or cathode, arcing phenomenon would happen under the application of high voltage. The more the arcing happened, the more damaged the cathode filament was, resulting in a low field emission characteristics. To bring their field emission properties of the filament into full play, avoiding adsorption of moisture and impurities in the air should be especially taken care in the storage of cathode filaments. In the vacuum seal process, the cathode filament needs to be given a fixed voltage under vacuum pumping to desorb and extract the adsorptive moisture by vacuum pumping equipment to avoid damage to the cathode filament. The results indicate that a CNC cathode filament with good field emission properties can be prepared at the growth temperature of 800℃ and growth time of 8 min. The nitrogen post-treatment can effectively promote the field emission characteristics of the cathode filaments. The treatment temperature of 200℃ , nitrogen flow of 500 sccm and holding time for 30 minutes is the optimum post-treatment parameters in this study.