Nanosecond Laser Surface Texturing of Crystalline Silicon in Ambient Air and Water

Abstract

Laser surface structuring is a versatile physical method to alter the surface morphology and subsequent surface properties of solid materials. In this work, we report the role of ambient conditions in nanosecond laser (Nd:YAG laser, τ = 7 ns) surface texturing of silicon, and the optical and morphological characterization of textured samples. We performed multiscale texturing (5 mm × 5 mm) on silicon by keeping the target in air as well as in water. The significant differences in the morphological and optical properties of textured samples indicate that the ambience (air or water) has a crucial role in laser material processing. 3D topographical analysis shows that nanosecond laser texturing performed in air offers more roughness to the silicon surface, which results in much reduced optical reflection (R ≈ 10% in the visible region) from the textured surface. Laser texturing has numerous applications in material science, industry, and biomedical fields and our results indicate that materials with specific surface roughness and reflectivity can be fabricated by changing the ambient conditions of laser texturing.