Revealing the Impact of Catalyst Phase Transition on Carbon Nanotube Growth by in Situ Raman Spectroscopy.

摘要

The physical state of the catalyst and its impact on the growth of single-walled carbon nanotubes (SWNTs) is the subject of a long-standing debate. We addressed it here using in situ Raman spectroscopy to measure Fe and Ni catalyst lifetimes during the growth of individual SWNTs across a wide range of temperatures (500 1400 C). The temperature dependence of the Fe catalyst lifetimes underwent a sharp increase around 1100 C due to a solidto- liquid phase transition. By comparing experimental results with the metal carbon phase diagrams, we prove that SWNTs can grow from solid and liquid phase-catalysts, depending on the temperature.