Hong Seunghyun, Jung Sehun, Choi Jaeboong, Kim Youngjin, Baik Seunghyun
SKKU Advanced Institute of Nanotechnology (SAINT) and School of Mechanical Engineering, Sungkyunkwan University, Suwon, KyungGi-Do 440-746, Korea.
Langmuir. 2007 Apr 24;23(9):4749-52. doi: 10.1021/la070206e. Epub 2007 Mar 31.
Alternating current dielectrophoresis has attracted considerable attention as a possible candidate to separate single-walled carbon nanotubes according to electronic types. Recently, the significant effect of surface charge on the polarizability of semiconducting nanotubes was demonstrated using comparative Raman spectroscopic studies. Here we present electrical transport characteristics of surface-charge-controlled, dielectrophoretically deposited nanotube arrays. The surface charge was controlled using cationic/anionic surfactant mixtures. Complete separation between metallic and semiconducting species was achieved at the electric field frequency of 10 MHz only when the surface charge of nanotubes was neutralized, which is consistent with previous Raman investigation. A theoretical analysis, using zeta potential information as input, further supported the experimental observation.
交流介电泳作为一种根据电子类型分离单壁碳纳米管的可能方法，已经引起了广泛关注。最近，通过比较拉曼光谱研究证明了表面电荷对半导体纳米管极化率的显著影响。在此，我们展示了表面电荷控制的介电泳沉积纳米管阵列的电输运特性。使用阳离子/阴离子表面活性剂混合物控制表面电荷。仅当纳米管的表面电荷被中和时，在10 MHz的电场频率下才能实现金属和半导体物种之间的完全分离，这与之前的拉曼研究一致。以zeta电位信息作为输入的理论分析进一步支持了实验观察结果。
