탄소 나노튜브의 합성 및 전계방출 소자 응용 연구 = Synthesis of carbon nanotube and it's application for field emission device

다국어 초록 (Multilingual Abstract)

Carbon nanotube (CNT) is hollow tube formed by roll-up of graphite sheet(s) into cylinder. It is divided into single-wall carbon nanotube (SWNT) and multi-wall carbon nanotube (MWNT) depending on the number of the graphite sheets forming the tube wall CNT was disclosed for the first time by Iijima in 1991 as MWNT type. The distance between the atomic graphitic sheets of the wall in MWNT is ∼0.34 nm that is similar to the interplanar spacing in graphite. The diameter of MWNT ranges from a few to tens of nanometers and its length from micron meters to millimeters showing its one dimensional nature. In addition to this one dimensional quantum geometry with very high aspect ratios. other properties originating from the characteristics of the atomic carbon and nano structure such as good electrical conductivity, stubborn mechanical property, nano size cavity, etc. have motivated its use in various applications.
A detailed systematic study on the growth morphology of carbon nanotubes (CNTs) on Si in atmospheric pressure thermal chemical vapor deposition was undertaken. The role of NH_(3) for vertical alignment of CNTs was investigated. The direct cause for the alignment was a dense distribution of the catalytic metal particles, but that the particles are maintained catalytically active under amorphous carbon deposits was established by NH_(3) . It allows a dense nucleation of the CNTs, and consequently, assists vertical alignment through entanglement and mechanical leaning among the tubes. The CNTs grew in a base growth mode and a few direct evidences were presented. Since Ni is consumed both by silicide reaction and by capture into the growing tube, the growth stops when Ni is totally depleted. It occurs earlier for smaller particles, and thus a long time of growth results in a thin bottom with poor adhesion.
Well-aligned carbon multiwall nanotubes (MWNT) arrays have been continuously synthesized by thermal chemical vapor deposition method involving the pyrolysis of acetylene gas on catalytic metal coated on substrate. Aligned carbon nanotubes (CNTs) have attracted great attention because of their unique structural and electrical properties, which can be used in a broad range of potential applications.
Here, we propose on synthesis of carbon nanotube arrays in the trench structure for triode type field emitters and SOG (spin on glass) coating process. Carbon nanotube arrays stick to the substrate firmly due to SOG coating. Trimming process was conducted to get a uniform height of carbon nanotubes related to uniform current density for large area, with a goal of fabricating their display application and better controllability of carbon nanotubes. We observed densely aligned carbon nanotube arrays and investigated emission property of carbon nanotube arrays in the trench structure. To fabricate CNT based triode structure field emitter, conventional semiconductor process was used, such as photolithography, etching, and lift-off process. It is essential to form selective growth of carbon nanotubes for FED emitters and electronic devices
We have produced an aligned carbon Nanotube arrays in the trench structure that has a side length of 5㎛ by 5㎛, 10㎛ by l0㎛ respectively and 10㎛ depth in order to CNTs fabricated field emitters using thermal chemical vapor deposition. These nanotubes with diameters in a range of 40∼6Onm are well graphitized and typically consist of above 40 concentric shells of carbon sheets. Furthermore, we obtained CNT mays with uniform length and high controllability through SOG coating process and trimming process. These results bring us closer to achieving structural control over nanotubes for adapting to the field emitters.
A new approach to synthesizing carbon nanotubes on substrates was undertaken. Instead of conventional metallic catalyst nanoparticles such as Ni, Co, and Fe, which are usually deposited by physical vapor deposition, a magnetic fluid of surfacted magnetite nanoparticles can be successfully applied by a simple spin coating method for carbon nanotubes synthesis in chemical vapor deposition method. Mixing with polyvinyl alcohol before applying on plane substrates controlled the viscosity of the magnetic fluid. The polyvinyl alcohol evaporates during heat-up to the synthesis, and vertically aligned dense carbon nanotubes could be grown on the agglomerated magnetite nanoparticles.

목차 (Table of Contents)

• 목차 = ⅰ
• 감사의 글 = ⅶ
• List of Figures = ⅷ
• List of Tables = ⅹⅸ
• Ⅰ. 서론 및 배경 = 1
• Ⅰ.1. 서론 및 실험목적 = 1
• Ⅰ.2. 탄소 나노튜브 = 7
• Ⅰ.2.1. 탄소 재료의 역사 = 7
• Ⅰ.2.2. 플러린에서 파생된 탄소 나노튜브 = 10
• Ⅰ.2.3. 단중벽 탄소 나노튜브 = 13
• Ⅰ.2.4. 다중벽 탄소 나노튜브 = 17
• Ⅰ.3. 탄소 나노튜브의 특성 = 19
• Ⅰ.3.1. 탄소 나노튜브의 구조적 특성 = 19
• Ⅰ.3.2. 탄소 나노튜브의 기계적 특성 = 27
• Ⅰ.3.3. 탄소 나노튜브의 전기적 특성 = 29
• Ⅰ.3.4. 탄소 나노튜브의 전계방출 특성 = 34
• Ⅰ.1.1.a. 전계방출 이론 = 34
• Ⅰ.1.1.b. 탄소 나노튜브의 전계방출 특성 = 36
• Ⅰ.4. 탄소 나노튜브의 합성기술 = 38
• Ⅰ.4.1. 아크방전법 및 레이저 증착법 = 38
• Ⅰ.4.2. 화학 기상 증착법 = 43
• Ⅰ.4.3. 플라즈마 화학 기상 증착법 = 46
• Ⅰ.4.4. 기상 합성법 = 49
• Ⅰ.5. 탄소 나노튜브의 응용 = 51
• Ⅰ.5.1. 탄소 나노튜브를 기반으로 한 전계방출 소자 = 51
• Ⅰ.5.2. 에너지 저장 = 54
• Ⅰ.5.3. 복합체 = 59
• Ⅰ.6. 참고문헌 = 61
• Ⅱ. 화학기상증착법을 이용한 탄소 나노튜브의 합성 = 69
• Ⅱ.1. 서론 및 실헝목적 = 69
• Ⅱ.2. 실험방법 및 기구 = 70
• Ⅱ.2.1. 스퍼터링을 이용한 박막 증착 = 70
• Ⅱ.2 2. 화학 기상 증착 장치 = 73
• Ⅱ.3. 실험결과 = 75
• Ⅱ.3.1. 촉매 금속의 형성 및 열 처리 후 표면 분석 = 75
• Ⅱ.3.2. 촉매 금속 표면 형상에 따른 CNT 합성 결과 = 95
• Ⅱ.3.3. 합성 온도에 따른 CNT 합성 결과 = 107
• Ⅱ.3.4. 합성 시간에 따른 CNT 합성 결과 = 111
• Ⅱ.4. 결론 = 115
• Ⅱ.5. 참고문헌 = 117
• Ⅲ. CNT 합성시 암모니아 가스의 역할 = 119
• Ⅲ.1. 서론 및 실험목적 = 119
• Ⅲ.2. 실험방법 및 기구 = 121
• Ⅲ.3. 실험결과 = 122
• Ⅲ.3.1. 암모니아 가스의 역할 = 122
• Ⅲ.3.2. 탄소 나노튜브의 수직 정렬과 암모니아 가스의 역할 = 146
• Ⅲ.4. 결론 = 162
• Ⅲ.5. 참고문헌 = 164
• Ⅳ. 플라즈마 장치를 이용한 탄소 나노튜브의 합성 = 165
• Ⅳ.1. 서론 및 실험목적 = 165
• Ⅳ.2. 실험방법 및 기구 = 166
• Ⅳ.2.1. 플라즈마 화학 기상 증착기 = 166
• Ⅳ.2.2. 실험방법 = 168
• Ⅳ.3. 실험결과 = 169
• Ⅳ.3.1. 촉매 금속에 의한 CNT 합성 결과 = 169
• Ⅳ.3.2. 전처리 과정에서의 암모니아 유량과 파워에 의한 영향 = 174
• Ⅳ.3.3. 가스 유량비에 따른 탄소 나노튜브의 합성 경향 = 181
• Ⅳ.3.4. 성장중 플라즈마 파워에 의한 탄소 나노튜브의 합성경향 = 187
• Ⅳ.4. 결론 = 191
• Ⅳ.5. 참고문헌 = 193
• Ⅴ. 탄소 나노튜브의 성장 메케니즘 = 194
• Ⅴ.1. 서론 및 실험목적 = 194
• Ⅴ.2. 실험결과 = 195
• Ⅴ.2 1. 탄소 나노튜브의 성장 메커니즘 = 195
• Ⅴ.2.2. 탄소 나노튜브의 성장 모드 = 204
• Ⅴ.2.3. 탄소 나노튜브의 수직 성장 = 209
• Ⅴ.3. 결론 = 211
• Ⅴ.4. 참고문헌 = 212
• Ⅵ. CNT-FEA 제작 및 전계 방출 특성 측정 = 214
• Ⅵ.1. 서론 및 실험목적 = 214
• Ⅵ.2. 실험방법 및 기구 = 217
• Ⅵ.2.1. 전계 방출 특성 이론 = 217
• Ⅵ.2.2. 탄소 나노튜브의 전계 방출 소자 제작 = 220
• Ⅵ.2.3. 2극관 CNT-FEA 제작을 위한 구조 = 224
• Ⅵ.2.4. 3극관 CNT-FEA 제작을 위한 구조 = 225
• Ⅵ.2.5. 전계 방출 특성 측정 = 228
• Ⅵ.3. 실험결과 = 230
• Ⅵ.3.1. 선택적 영역에서의 탄소 나노튜브 합성 = 230
• Ⅵ.3.2. Trench 구조에서의 탄소 나노튜브 합성 = 238
• Ⅵ.3.3. 전계 방출 특성 향상을 위한 구조 개발 = 242
• Ⅵ.3.4. 2극관 구조에서의 전계방출 특성 = 260
• Ⅵ.4. 결론 = 273
• Ⅶ. 탄소 나노튜브의 대량 합성 = 274
• Ⅶ.1. 서론 및 실험목적 = 274
• Ⅶ.2. 실험방법 및 기구 = 276
• Ⅶ.2.1. 나노 파우더 준비 = 276
• Ⅶ.2.2. 자성 유체의 제조방법 = 278
• Ⅶ.3. 실험결과 = 282
• Ⅶ.3.1. 나노 파우더 위에서 합성된 탄소 나노튜브 = 282
• Ⅶ.3.2. 자성 유체 위에서 합성된 탄소 나노튜브 = 294
• Ⅶ.3.3. 여러 가지 기판에서의 CNT 합성 = 317
• Ⅶ.4. 결론 = 323
• Ⅶ.5. 참고문헌 = 325