Laser Patterning of Aligned Carbon Nanotubes Arrays: Morphology, Surface Structure, and Interaction with Terahertz Radiation

Abstract

The patterning of arrays of aligned multi-walled carbon nanotubes (MWCNTs) allows creating metastructures for terahertz (THz) applications. Here, the strips and columns from MWCNTs vertically grown on silicon substrates are prepared using CO2 laser treatment. The tops of the patterned arrays are flat when the laser power is between 15 and 22 W, and craters appear there with increasing power. Laser treatment does not destroy the alignment of MWCNTs while removing their poorly ordered external layers. The products of oxidative destruction of these layers deposit on the surfaces of newly produced arrays. The oxygen groups resulting from the CO2 laser treatment improve the wettability of nanotube arrays with an epoxy resin. We show that the patterned MWCNT arrays absorb the THz radiation more strongly than the as-synthesized arrays. Moreover, the pattern influences the frequency behavior of the absorbance.

Construction of Medusa‐Like Adhesive Carbon Nanotube Array Induced by Deformation of Alumina Sheets

“…high-speed rotating tool; transferring/imprinting some of the nanotubes by micro molds; [18,19] or laser/electron beam ablation to remove partial array, to process the array into a desired structure. [20,21] Capillary forces of solvent evaporation have also been used to fully or partially densify the array to obtain specific structures. [22,23] Nevertheless, these efforts either perform structural modifications at the expense of mechanical damage to the nanotubes, by discarding partial nanotubes or simply divide the growth into multiple identical regions without changing the density, orientation and degree of alignment of the nanotubes therein, let alone the binary structure of the arrays.…”

“…Alternatively, some post‐growth techniques are also employed, like the micromechanical bending process, [ 17 ] which bends and flattens the desired regions of surface nanotubes with the movement of a high‐speed rotating tool; transferring/imprinting some of the nanotubes by micro molds; [ 18,19 ] or laser/electron beam ablation to remove partial array, to process the array into a desired structure. [ 20,21 ] Capillary forces of solvent evaporation have also been used to fully or partially densify the array to obtain specific structures. [ 22,23 ]…”