State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001, People's Republic of China.
Nanotechnology. 2017 Nov 24;28(47):475601. doi: 10.1088/1361-6528/aa8dd9.
In order to confirm the key role of Ar ion bombardment in the growth feature of nanostructured carbon materials (NCMs), here we report a novel strategy to create different Ar ion states in situ in plasma enhanced chemical vapor deposition (PECVD) by separating catalyst film from the substrate. Different bombardment environments on either side of the catalyst film were created simultaneously to achieve multi-layered structural NCMs. Results showed that Ar ion bombardment is crucial and complex for the growth of NCMs. Firstly, Ar ion bombardment has both positive and negative effects on carbon nanotubes (CNTs). On one hand, Ar ions can break up the graphic structure of CNTs and suppress thin CNT nucleation and growth. On the other hand, Ar ion bombardment can remove redundant carbon layers on the surface of large catalyst particles which is essential for thick CNTs. As a result, the diameter of the CNTs depends on the Ar ion state. As for vertically oriented few-layer graphene (VFG), Ar ions are essential and can even convert the CNTs into VFG. Therefore, by combining with the catalyst separation method, specific or multi-layered structural NCMs can be obtained by PECVD only by changing the intensity of Ar ion bombardment, and these special NCMs are promising in many fields.
为了确认 Ar 离子轰击在纳米结构碳材料（NCMs）生长特征中的关键作用，我们在这里报告了一种通过将催化剂薄膜与基底分离，在等离子体增强化学气相沉积（PECVD）中原位创造不同 Ar 离子状态的新策略。通过同时在催化剂薄膜两侧创建不同的轰击环境，实现了多层结构的 NCMs。结果表明，Ar 离子轰击对 NCMs 的生长至关重要且复杂。首先，Ar 离子轰击对碳纳米管（CNTs）既有积极影响，也有消极影响。一方面，Ar 离子可以打断 CNTs 的图形结构，抑制薄 CNT 的成核和生长。另一方面，Ar 离子轰击可以去除大催化剂颗粒表面多余的碳层，这对于厚 CNTs 是必不可少的。因此，CNTs 的直径取决于 Ar 离子状态。对于垂直取向的少层石墨烯（VFG），Ar 离子是必不可少的，甚至可以将 CNTs 转化为 VFG。因此，通过结合催化剂分离方法，仅通过改变 Ar 离子轰击的强度，就可以通过 PECVD 获得特定或多层结构的 NCMs，这些特殊的 NCMs在许多领域具有广阔的应用前景。
