Orientational alignment of semiconducting carbon nanotubes by the parallel steps of high-index copper foils

Abstract

Numerous research efforts have focused on the deposition and morphology control of semiconducting single-walled carbon nanotubes (s-SWCNTs) to exploit their extraordinary properties to fulfill in building next-generation electronics. However, it is difficult to realize s-SWCNT arrays at the controlled densities and alignments desired for high-performance devices. Here, we developed a novel approach to control the morphology and alignment of s-SWCNTs. Random s-SWCNT networks came into being well-aligned s-SWCNT arrays (within the alignment of 16.9°) along with the recrystallization of copper foils from polycrystalline to single-crystalline. Grain boundary migration induced motion and alignment of s-SWCNTs. In this way, high-quality s-SWCNTs were assembled into well-aligned CNT arrays on single-crystal high-index copper foils. Furthermore, theoretical calculations confirm that the strong binding energy between the s-SWCNTs and the copper edge steps leads to the orientational alignment of the s-SWCNTs on the copper surface.