Studies on large area and low temperature fabrication and reaction dynamics of aligned carbon nanostructures

本文对垂直排列碳纳米结构的制备进行了研究，并成功地创造了新型垂直排列碳纳米结构。采用电容耦合等离子体射频等离子体增强化学气相沉积技术制备了二维碳纳米结构（CNWs）。在不注入H自由基的情况下，不制备CNWs。CNWs的形态与碳源气体类型（C_2F_6、CF_4、CHF_3a、CH_4等）有关。CNWs生长在无催化剂的Si、SiO_2和不锈钢基底上，与基底材料无关。通过倾斜衬底，成功地制备了条纹结构CNWs。采用微波等离子体增强化学气相沉积技术合成了致密碳纳米管。采用准分子激光烧蚀法制备了Co纳米颗粒作为催化剂。通过改变Co催化纳米颗粒的沉积时间，可以控制直径约为6 nm的CNTs的密度。CNTs在生长的前3min生长迅速，随后生长速度明显下降。在生长初期，CNTs以300 nm/s的超高速率生长。研制了一种微波激发非平衡常压等离子体源，并将其应用于碳纳米管的化学气相沉积。以He/H_2/CH_4和He/H_2/CF_4的混合物为原料，在600℃低温下成功合成了多壁碳纳米管。

The investigation shown in the following as the fabrication of the vertically aligned carbon nanostructures has been carried out, and it succeeded in the creation of the novel vertically aligned carbon nanostructures.1.Fabrication of carbon nanowalls (CNWs)Two-dimensional carbon nanostructures (carbon nanowalls : CNWs) were fabricated using capacitively coupled plasma radio-frequency plasma-enhanced chemical vapor deposition assisted by H radical injection. In the case of the deposition without H radical injection, CNWs were not fabricated. The morphologies of CNWs were dependent on the types of carbon source gases (C_2F_6,CF_4,CHF_3a,CH_4,etc). CNWs were grown on Si,SiO_2, and stainless steel substrates without catalyst, and independent of substrate materials. It succeeded the fabrication of the CNWs with stripe structure by tilting the substrates.2.Dense carbon nanotubesCarbon nanotubes (CNTs) were synthesized using microwave plasma-enhanced chemical vapor deposition. Co nanoparticles as catalyst were prepared using excimer laser ablation. The density of CNTs with a diameter of approximately 6 nm was controllable by changing the deposition time of Co catalytic nanoparticles. CNTs were grown rapidly during the first 3min of growth, then the growth rate of CNTs decreased markedly. At early stage of growth, the CNTs grew at an extremely high rate of 300 nm/s.3.Growth of carbon nanotubes by atmospheric-pressure plasmaA microwave excited non-equilibrium atmospheric pressure plasma source was developed and applied to chemical vapor deposition of carbon nanotubes (CNTs). Multiwalled CNTs were successfully synthesized at a low temperature of 600℃ by using mixtures of He/H_2/CH_4 and He/H_2/CF_4.