Facile Preparation of Free-Standing Carbon Nanotube Arrays Produced Using Two-Step Floating-Ferrocene Chemical Vapor Deposition

A two-step floating-ferrocene chemical vapor deposition method has been devised for the preparation of single-layered aligned carbon nanotube (CNT) arrays. In the first step, uniform Fe catalysts are in situ produced and coated on a Si substrate from ferrocene; single-layered CNT arrays are prepared on these catalysts from ethylene in the second step. The effect of ferrocene loading on the distribution of Fe catalysts, as well as the morphology, diameter, and height of the CNT arrays, was investigated. A novel vacuum extraction process was employed to release the as-prepared CNT array from the Si wafer after water etching at 750 °C. The structural integrity of the free-standing arrays was preserved after the detachment process. The interface between the substrate and the as-grown CNT array was examined. The Fe catalyst distribution on the Si substrate remained homogeneous when the CNT array was removed, and the tops and bottoms of the arrays had different structures, suggesting that the arrays were formed predominantly by a base-growth mode. These free-standing arrays could potentially be applied in membrane or electronic applications.