Electrochemical identification of metallic and semiconducting single-walled carbon nanotubes

Single-walled carbon nanotubes (SWNTs) are promising building blocks for nanoelectronics. However, because of the mixture of metallic and semiconducting single-walled carbon nanotubes (m-SWNTs and s-SWNTs), it is necessary to identify them for nanodevice integerations. In this work, we have observed obvious electrodeposition differences of ultralong m-SWNTs and s-SWNTs. Using high-resolution atomic force microscopy (AFM) and field emission scanning electron microscopy (FE-SEM), particle densities along different carbon nanotubes were examined. Interestingly, m-SWNTs and s-SWNTs showed obviously different deposition behaviors, i.e., exponential decay of particle densities with different decay coefficients. This electrochemical approach can be used for a simple identification of m-SWNTs and s-SWNTs.