The low temperature nucleation and high yield growth of CNTs with their diverse range of layered structures and shapes is of significant interest to the research community in view of obtaining distinctive properties necessary for specific applications. In this regard, several strategies have been employed to control the growth characteristics of CNTs. In the present investigation, the low temperature growth of CNTs has been enabled using CO₂ as a suitable oxidizing gas. CNTs have been grown via an optimum etching process conducted under diffuse plasma generated using a specially designed shadow mask assembly that shields the growth surface from direct plasma bombardment, and subsequent abrasive etching by the reactive plasma species. Furthermore, CO₂ as a component in the plasma facilitates the elimination of amorphous carbonaceous components from the surface of the CNTs. The growth of narrow CNTs has been achieved via the formation of a low diameter (~20 nm) catalyst comprised of Fe nano-particles grown in a low temperature (10 °C) chemical process under an inert atmosphere via simultaneous aerial oxidation and neutralization in a single step. Further plasma optimization by controlling the MW power has facilitated the growth of CNTs with controlled diameters, wall numbers and different morphologies (e.g., Y-junction and bamboo-shaped MWCNTs, and very low diameter (~1.5 nm) SWCNTs). The tip growth mechanism for CNT nucleation has been established using HR-TEM, in which the Fe catalyst nanoparticles are detected within the top shell of the growing CNTs.

考虑到获得特定应用所必需的独特性能，具有各种层状结构和形状的CNT的低温成核和高产率的增长引起了研究界的极大兴趣。在这方面，已经采用了几种策略来控制CNT的生长特性。在本研究中，使用CO ₂作为合适的氧化气体已经能够实现CNT的低温生长。CNT是通过最佳腐蚀工艺生长的，该腐蚀工艺是在使用专门设计的荫罩组件产生的扩散等离子体下进行的，该荫罩组件可保护生长表面免受直接等离子体轰击，并随后通过反应性等离子体进行磨蚀。此外，CO ₂作为等离子体中的一种组分，有助于从CNT的表面消除无定形的碳质组分。窄碳纳米管的生长是通过形成低直径（〜20 nm）的催化剂实现的，该催化剂包含在惰性气氛下通过低温（10°C）化学过程生长的铁纳米颗粒，同时通过空气中的氧化和中和反应一步。通过控制MW功率进行的进一步等离子体优化，已经促进了具有受控直径，壁数和不同形态（例如Y型结和竹形MWCNT，以及非常小直径（约1.5 nm）的SWCNT）的CNT的生长。已经使用HR-TEM建立了CNT成核的尖端生长机理，其中在生长的CNT的顶部外壳中检测到Fe催化剂纳米颗粒。