Horizontal arrays of single-walled carbon nanotubes (SWCNTs) have shown immense potential for application in emerging devices due to their excellent electrical and thermal properties. The direct growth of SWCNT arrays using high-activity metal catalysts is one of the promising methods to approach the mass production of dense SWCNT arrays. However, an inevitable obstacle lies in the post-purification of metal residual. Herein, a sowing strategy to prepare size-tunable potassium chloride (KCl) catalysts for the efficient growth of the SWCNT array with a density of 10 tubes per micron is reported. Through a controllable etching process, numerous surface defects (e.g., vacancies and kinks) are uniformly generated on the substrate as seed pit-like sites for the accommodation and anchoring of catalysts. The well-distributed KCl catalysts with a homogeneous size of ≈1.4 nm enable the growth of ≈1.3 nm SWCNTs through a vapor-liquid-solid mechanism. Importantly, 94 at.% KCl catalysts can be dramatically removed through a simple water-washing process, thus leaving contamination-free SWCNT arrays behind. Interestingly, 85% of nanotubes show metallic properties, which is demonstrated by the combination of electrical characterization and the multi-laser Raman spectroscopy. This sowing strategy contributes to the direct growth of uncontaminated high-density SWCNT arrays.

中文翻译：

---

播种清洁释放盐催化剂合成无污染单壁碳纳米管阵列


单壁碳纳米管 （SWCNT） 的水平阵列由于其出色的电气和热性能，在新兴器件中显示出巨大的应用潜力。使用高活性金属催化剂直接生长 SWCNT 阵列是实现密集 SWCNT 阵列大规模生产的有前途的方法之一。然而，一个不可避免的障碍在于金属残留物的后净化。在此，报道了一种制备尺寸可调氯化钾 （KCl） 催化剂的播种策略，用于密度为每微米 10 管的 SWCNT 阵列的高效生长。通过可控的蚀刻工艺，许多表面缺陷（例如空位和扭结）在衬底上均匀产生，作为催化剂容纳和锚定的种子坑状位点。分布均匀的 KCl 催化剂具有 ≈1.4 nm 的均匀尺寸，可通过气-液-固机制生长 ≈1.3 nm SWCNTs。重要的是，通过简单的水洗过程，可以显著去除 94 at.% KCl 催化剂，从而留下无污染的 SWCNT 阵列。有趣的是，85% 的纳米管表现出金属特性，电学表征和多激光拉曼光谱的结合证明了这一点。这种播种策略有助于未受污染的高密度 SWCNT 阵列的直接生长。