Atomic-Scale dynamic evolution and interfacial interactions in femtosecond laser cutting of SWCNTs on silicon substrate

To resolve the atomic scale interplay between structural parameters and cutting dynamics during laser processing, molecular dynamics simulations were employed to investigate femtosecond laser cutting of single walled carbon nanotubes (SWCNTs) on silicon substrates while systematically excluding external processing variables. The entire cutting process comprises four distinct stages including energy accumulation, bond cleavage initiation, bond cleavage plateau, and cooling-driven reconstruction. SWCNTs diameter servers as a dominant regulatory factor. Larger-diameter SWCNTs like (11,11)) present a higher diffusion coefficients and stronger interfacial bonding via Si-C covalent bonds with deep atomic embedding (exceed 0.6 nm). While chirality plays a secondary role by modulating the intrinsic structural stability of nanotubes. Meanwhile, the silicon substrate only exhibits limited surface amorphization (<5 layers) and spontaneous structural self-healing during the cooling stage. This work establishes a quantitative atomic-scale relationship between SWCNTs geometric characteristics and laser cutting performance, providing fundamental insights into interfacial optimization and precise processing of carbon-based nanomaterials for microelectronic applications. © 2026 Elsevier Ltd