External radiative source assisted growth of highly aligned single-walled carbon nanotube array

Abstract

Direct growth of single-walled carbon nanotubes (SWNTs) array based on catalyst design is one of the important strategies towards SWNT-based electronic applications, yet facing a fundamental thermodynamic conflict: high temperatures prefer chirality purity but disrupt lattice-aligned growth by amplifying thermophoretic forces (F_th). Here, we resolved this paradox by decoupling catalytic growth and orientation processes through spatially engineered temperature gradients. An external thermal radiation field is introduced to suppress F_th at the catalyst-substrate interface while preserving high-temperature catalytic activity, achieving a lattice orientation and up to tenfold density increasing under conventional non-orientated temperature. Furthermore, experimental and computational simulations quantitively described the transition between lattice orientation and gas flow orientation when temperature increases, and deeply expounded the orientation mechanism with external thermal radiation from the microscopic perspective. This strategy demonstrates the universality across catalysts (quantum dots, Fe and Cu), thus enabling the co-realization of chirality-specific and high-density SWNT arrays, promoting carbon-based electronics toward practical applications.