Suspended and highly aligned carbon nanotube thin-film structures using open microfluidic channel template

We demonstrate microfabrication and characterization of suspended carbon nanotube (CNT) thin-film structures possessing a high degree of alignment. The alignment of CNT was achieved by the open microfluidic channel template and enhanced by heating the CNT dispersion, which was scalable and processable. The degree of alignment, as characterized by Raman spectroscopy, yielded a high G- to D-band intensity ratio of 22 along the fluid flow direction. The microfluidic alignment scheme was combined with microfabrication techniques for the fabrication of suspended thin-film structures. The sidewall of CNT film pattern, left in fluidic channel removal process, was successfully removed by oxygen plasma etching with a masking layer of photoresist, as shown by scanning electron microscopy and atomic force microscopy. The resistivity of the aligned CNT film was found to be 2.2 × 10^-3 Ω cm, smaller than that of films aligned by other techniques. The aligned CNT film was released by etching a sacrificial layer. Mechanical characterization showed a nominal Young's modulus of 635 GPa and yield strength of 2.4 GPa on the assumption of a fixed-fixed Euler beam. The reliable, scalable and processable fabrication process, the resulting high conductivity and excellent mechanical properties may enable aligned CNT films to be a potent candidate for electromechanical device applications.