Direct current injection and thermocapillary flow for purification of aligned arrays of single-walled carbon nanotubes

Articles you may be interested in Effect of synthesis and acid purification methods on the microwave dielectric properties of single-walled carbon nanotube aqueous dispersions Appl. Directed assembly of solution processed single-walled carbon nanotubes via dielectrophoresis: From aligned array to individual nanotube devices Current on/off ratio enhancement through the electrical burning process in ambient with/without oxygen for the generation of high-performance aligned single-walled carbon nanotube field effect transistors Appl. Aligned arrays of semiconducting single-walled carbon nanotubes (s-SWNTs) represent ideal configurations for use of this class of material in high performance electronics. Development of means for removing the metallic SWNTs (m-SWNTs) in as-grown arrays represents an essential challenge. Here, we introduce a simple scheme that achieves this type of purification using direct, selective current injection through interdigitated electrodes into the m-SWNTs, to allow their complete removal using processes of thermocapillarity and dry etching. Experiments and numerical simulations establish the fundamental aspects that lead to selectivity in this process, thereby setting design rules for optimization. Single-step purification of arrays that include thousands of SWNTs demonstrates the effectiveness and simplicity of the procedures. The result is a practical route to large-area aligned arrays of purely s-SWNTs with low-cost experimental setups. V C 2015 AIP Publishing LLC.