Study on field emission characteristics of flake-like nanocrystalline graphite films fabricated by CVD method

• Main Author: 李東哲
• Other Authors: 蔡宏營
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/91908151436754604991

碩士 === 國立清華大學 === 動力機械工程學系 === 101 === In our research, flake-like nanocrystalline graphite(NCG) films were grown on the silicon substrate using hot-filament chemical vapor deposition(HFCVD) system. We observed NCG’s surface morphology, uniformity, crystal quality and measured their field emission properties after changing process parameters like gas ratio, growth temperature, adding nitrogen and using pretreatment. Afterward we fabricated the Ultra-nano crystalline diamond(UNCD) and NCG composite films and discussed their properties. Finally, we fabricated NCG, UNCD and UNCD/NCG pyramid-type field emission arrays by using lithography technique, anisotropic etching technique and molding technique. The experimental showed that the turn-on field on the NCG film grown by using 9% methane concentration was 12 V/μm. After adding nitrogen, the turn-on field decreased to about 6~8 V/μm. The turn-on field on the UNCD/NCG composite films were about6~7 V/μm. We observed the reproducibility on UNCD/NCG composite films’ field emission behavior due to the high thermal conductivity and mechanical strength on UNCD. For improving the field emission facter, we fabricated the pyramid-type field emission arrays. They were 8.4 μm in height, 12 μm in base length and 3 in the pitch to base length ratio . The lowest turn-on field of 4.78 V/μm can be obtained in NCG pyramid-type field emission arrays.