Fig. 2: Morphology and Formation Mechanism of Sub-50 nm Nano-line.

a SEM images of nano-line formed in Sb2S3 films through microsphere femtosecond irradiation at a laser fluence of 0.12 mJ cm⁻² and a scanning speed of 150 μm s⁻¹. Corresponding b three-dimensional morphology and c cross-sectional profile of the nano-line obtained by AFM measurement. d Schematic of nano-lines formation mechanism in Sb2S3 films during the molten state under high-repetition-rate femtosecond laser irradiation