Department of Chemistry, Duke University, Durham, North Carolina 27708, USA.
J Am Chem Soc. 2012 Aug 29;134(34):14019-26. doi: 10.1021/ja3038992. Epub 2012 Aug 16.
The presence of metallic nanotubes in as-grown single walled carbon nanotubes (SWNTs) is the major bottleneck for their applications in field-effect transistors. Herein, we present a method to synthesize enriched, semiconducting nanotube arrays on quartz substrate. It was discovered that introducing appropriate amounts of water could effectively remove the metallic nanotubes and significantly enhance the density of SWNT arrays. More importantly, we proposed and confirmed that the high growth selectivity originates from the etching effect of water and the difference in the chemical reactivities of metallic and semiconducting nanotubes. Three important rules were summarized for achieving a high selectivity in growing semiconducting nanotubes by systematically investigating the relationship among water concentration, carbon feeding rate, and the percentage of semiconducting nanotubes in the produced SWNT arrays. Furthermore, these three rules can be applied to the growth of random SWNT networks on silicon wafers.
金属纳米管在生长的单壁碳纳米管（SWNTs）中的存在是其在场效应晶体管中应用的主要瓶颈。在此，我们提出了一种在石英衬底上合成富集、半导体纳米管阵列的方法。研究发现，引入适量的水可以有效地去除金属纳米管，并显著提高 SWNT 阵列的密度。更重要的是，我们提出并证实了高生长选择性源于水的蚀刻效应以及金属和半导体纳米管之间化学反应性的差异。通过系统研究水浓度、碳进料速率和所生产的 SWNT 阵列中半导体纳米管的百分比之间的关系，我们总结了实现高选择性生长半导体纳米管的三个重要规则。此外，这些规则可应用于硅片上随机 SWNT 网络的生长。
