Yu Qingkai, Qin Guoting, Li Hao, Xia Zhenhai, Nian Yibo, Pei Shin-Shem
Texas Center for Advanced Materials, Department of Electrical and Computer Engineering, University of Houston, Houston, Texas 77204, USA.
J Phys Chem B. 2006 Nov 16;110(45):22676-80. doi: 10.1021/jp064875x.
As a promising one-dimensional material for building nanodevices, single-wall carbon nanotubes (SWNTs) should be organized into a rational architecture on the substrate surface. In this study, horizontally aligned SWNTs with two alignment modes were synthesized on the same R-plane sapphire wafer by chemical vapor deposition with cationized ferritins as catalysts. In the middle part of the wafer, SWNTs were aligned on the R-plane sapphire in the direction [1101]. At the edge of the wafer, SWNTs were aligned in the tangential direction to the wafer edge. The comparison of these two groups of SWNTs suggests the competition between the two alignment modes and indicates that atomic steps in high density have superior influence on the SWNTs' alignment to the crystal structure on the surface of the sapphire substrate. A "raised-head" growth mechanism model is proposed to explain why catalysts can stay active during the horizontally aligned growth of relatively long SWNTs with the strong interaction between SWNTs and the sapphire substrate.
作为一种用于构建纳米器件的有前途的一维材料，单壁碳纳米管（SWNTs）应在衬底表面上组织成合理的结构。在本研究中，通过以阳离子化铁蛋白为催化剂的化学气相沉积法，在同一R面蓝宝石晶片上合成了具有两种排列模式的水平排列的SWNTs。在晶片的中部，SWNTs在R面蓝宝石上沿[1101]方向排列。在晶片边缘，SWNTs沿与晶片边缘相切的方向排列。这两组SWNTs的比较表明了两种排列模式之间的竞争，并表明高密度的原子台阶对SWNTs排列的影响优于蓝宝石衬底表面的晶体结构。提出了一种“抬头”生长机制模型，以解释在SWNTs与蓝宝石衬底之间存在强相互作用的情况下，催化剂在相对较长的SWNTs水平排列生长过程中为何能够保持活性。
