Periodic structures on silicon surfaces induced by nanosecond laser pulses with low repetition rate

The formation of high-quality submicron patterns over large areas in media by lasers remains challenging. We report the formation of laser-induced periodic surface structures (LIPSS) on silicon using low-repetition-rate nanosecond pulses, thereby broadening the applicable techniques for their fabrication. The samples were irradiated using a low-repetition-rate nanosecond laser (λ = 532 nm, τ = 8 ns), forming laser-induced ripples on deposited silicon in air. The results show that the period of LIPSS on (the) silicon remains consistent (~530 ± 5 nm). The laser energy required to form ripples on the sample decreases with the increase in the number of laser pulses, which suggests the presence of an incubation effect. The genesis of LIPSS is attributed to interference involving the incident laser light and waves scattered by the surface. This study provides an important reference and support for the potential use of laser micromachining.