Barzegar Hamid R, Nitze Florian, Sharifi Tiva, Ramstedt Madeleine, Tai Cheuk W, Malolepszy Artur, Stobinski Leszek, Wågberg Thomas
J Phys Chem C Nanomater Interfaces. 2012 Jun 7;116(22):12232-12239. doi: 10.1021/jp211064c. Epub 2012 May 8.
We report on a dip-coating method to prepare catalyst particles (mixture of iron and cobalt) with a controlled diameter distribution on silicon wafer substrates by changing the solution's concentration and withdrawal velocity. The size and distribution of the prepared catalyst particles were analyzed by atomic force microscopy. Carbon nanotubes were grown by chemical vapor deposition on the substrates with the prepared catalyst particles. By decreasing the catalyst particle size to below 10 nm, the growth of carbon nanotubes can be tuned from few-walled carbon nanotubes, with homogeneous diameter, to highly pure single-walled carbon nanotubes. Analysis of the Raman radial breathing modes, using three different Raman excitation wavelengths (488, 633, and 785 nm), showed a relatively broad diameter distribution (0.8-1.4 nm) of single-walled carbon nanotubes with different chiralities. However, by changing the composition of the catalyst particles while maintaining the growth parameters, the chiralities of single-walled carbon nanotubes were reduced to mainly four different types, (12, 1), (12, 0), (8, 5), and (7, 5), accounting for about 70% of all nanotubes.
我们报道了一种浸涂法，通过改变溶液浓度和提拉速度，在硅片衬底上制备具有可控直径分布的催化剂颗粒（铁和钴的混合物）。通过原子力显微镜分析所制备催化剂颗粒的尺寸和分布。在带有所制备催化剂颗粒的衬底上通过化学气相沉积生长碳纳米管。通过将催化剂颗粒尺寸减小到10纳米以下，碳纳米管的生长可以从具有均匀直径的少壁碳纳米管调整为高纯度单壁碳纳米管。使用三种不同的拉曼激发波长（488、633和785纳米）对拉曼径向呼吸模式进行分析，结果表明不同手性的单壁碳纳米管具有相对较宽的直径分布（0.8 - 1.4纳米）。然而，在保持生长参数不变的情况下，通过改变催化剂颗粒的组成，可以将单壁碳纳米管的手性主要减少到四种不同类型，即(12, 1)、(12, 0)、(8, 5)和(7, 5)，占所有纳米管的约70%。
