Sadanadan B, Savage T, Bhattacharya S, Tritt T, Cassell Alan, Meyyappan M, Dai Z R, Wang Z L, Zidan R, Rao A M
Department of Physics and Astronomy, Clemson University, Clemson, South Carolina, USA.
J Nanosci Nanotechnol. 2003 Feb-Apr;3(1-2):99-103. doi: 10.1166/jnn.2003.186.
We have previously shown that high-purity multiwalled carbon nanotubes (pristine MWNTs) can be prepared from a mixture of xylene-ferrocene (99 at% C:1 at% Fe) inside a quartz tube reactor operating at approximately 700 degrees C. In a similar process, approximately 3 g of melamine (C3H6N6) was introduced during the growth of MWNTs to prepare nitrogen-doped nanotubes. The structural and electronic properties of nitrogen-doped MWNTs were determined by scanning electron microscopy, high-resolution transmission electron microscopy (HRTEM), electron energy loss spectroscopy (EELS), and thermopower measurements. The individual nitrogen-doped nanotube exhibits a bamboo-like structure and comprises 6-16 tube walls, as evidenced by HRTEM studies. The EELS measurements yielded an average nitrogen content of approximately 5 at% in the doped tubes. The thermoelectric power data of nitrogen-doped MWNTs remained negative even after exposure to oxygen for an extended period of time, suggesting that nitrogen doping of MWNTs renders them n-type, consistent with scanning tunneling spectroscopic studies on similar nanotubes.
我们之前已经表明，高纯度多壁碳纳米管（原始多壁碳纳米管）可以在石英管反应器中，于约700摄氏度的条件下，由二甲苯 - 二茂铁（99原子% C：1原子% Fe）的混合物制备而成。在类似的过程中，在多壁碳纳米管生长期间引入约3克三聚氰胺（C₃H₆N₆）以制备氮掺杂纳米管。通过扫描电子显微镜、高分辨率透射电子显微镜（HRTEM）、电子能量损失谱（EELS）和热电功率测量来确定氮掺杂多壁碳纳米管的结构和电子性质。高分辨率透射电子显微镜研究表明，单个氮掺杂纳米管呈现出竹节状结构，由6 - 16个管壁组成。电子能量损失谱测量得出掺杂管中的平均氮含量约为5原子%。即使在长时间暴露于氧气后，氮掺杂多壁碳纳米管的热电功率数据仍保持为负，这表明多壁碳纳米管的氮掺杂使其成为n型，这与对类似纳米管的扫描隧道光谱研究结果一致。
