Patterning of single walled carbon nanotubes using a low-fluence excimer laser photoablation process

Abstract

Carbon nanotube films were patterned by an excimer laser projection photoablation process at low incident energy conditions. The carbon nanotubes were deposited on a quartz substrate and then a conventional photoresist was coated on it as a photoablation assistor. The photoresist and the carbon nanotubes were simultaneously patterned by the projection photoablation process, and then the photoresist was removed. It was possible to make clean patterns of carbon nanotubes even though the incident fluence on the carbon nanotubes was significantly lower than the threshold energy otherwise needed for their direct ablation.

Patterning of Carbon Nanotubes by Material Assisted Laser Ablation Process

“…A thin layer of the residue layer and some textured layer are observable. In the conventional photoablation of polymers, such textured structure is not formed [17]. Therefore, we believe the textured residue layer results from a mixture of carbon nanotubes and the polymer.…”

“…In our previous work, although we were able to pattern carbon nanotubes using the MALA process, we could not fabricate clean patterns of carbon nanotubes because a residue layer remained after the process [16], [17]. Scanning electron microscopy (SEM) images of the typical residue layer after the In the illuminated region, where the polymer and carbon nanotubes are exposed to laser, a thin residue layer remains after the process.…”

“…This residue layer is formed after MALA process regardless of coating method of carbon nanotubes. The residue layer is formed with CVD grown carbon nanotubes [16] and [17], and solution-coated carbon nanotubes, in this paper. Also, this texture is formed regardless of type of substrates.…”

“…Recently, we reported a new patterning method called material assisted laser ablation (MALA) for patterning of carbon nanotubes and other nanowires that meets all of the requirements of high-volume production applications [16], [17].…”

“…Second, the patterning process should have high throughput and high yield in high-volume production applications. Direct ablation of carbon nanotubes can be another method of patterning the carbon nanotubes, but this method requires very high energy due to strong and stable bond structure of carbon nanotubes [16]. Substrates as well as devices that are fabricated on the substrate could be damaged by high-energy laser radiation, if direct ablation is used.…”