A rational design for the separation of metallic and semiconducting single-walled carbon nanotubes using a magnetic field. Issue 26 (17th June 2016) - Luo, Chengzhi
Abstract : We designed a novel magnetic field-assisted system to separate s-SWNTs with a purity of 99%, which is enough to construct high-performance transistors with a mobility of 230 cm 2 V −1 s −1 and an on/off ratio of 10 6 . Abstract : The separation of metallic (m-) and semiconducting (s-) single-walled carbon nanotubes (SWNTs) without causing contamination and damage is a major challenge for SWNT-based devices. As a facile and nondestructive tool, the use of a magnetic field could be an ideal strategy to separate m-/s-SWNTs, based on the difference of magnetic susceptibilities. Here, we designed a novel magnetic field-assisted floating catalyst chemical vapor deposition system to separate m-/s-SWNTs. Briefly, m-SWNTs are attracted toward the magnetic pole, leaving s-SWNTs on the substrate. By using this strategy, s-SWNTs with a purity of 99% could be obtained, which is enough to construct high-performance transistors with a mobility of 230 cm 2 V −1 s −1 and an on/off ratio of 10 6 . We also established a model to quantitatively calculate the percentage of m-SWNTs on the substrate and this model shows a good match with the experimental data. Furthermore, our rational design also provides a new avenue for the growth of SWNTs with specific chirality and manipulated arrangement due to the difference of magnetic susceptibilities between different diameters, chiralities, and types.