Fabrication of durable superhydrophilic silicon surfaces using nanosecond laser pulses

Abstract

In this work, we report the fabrication and characterization of large area micro-/nano-textured silicon surfaces using laser pulses of nanoseconds duration. An area of 6 × 6 mm 2 has been textured by the parallel line scanning method to create hierarchical structures, consisting of microscale channels and self-organized surface nano-capillaries decorated with randomly distributed silicon nanoparticles. The combination of micro-channels and nano-capillaries results in a superhydrophilic silicon surface, with the contact angle reduced substantially from about 80 ° to nearly 5 °. In contrast to most of the reports given in the literature, the superhydrophilicity of the surface remains stable without a shift to hydrophobicity, even after exposure to the atmosphere for about three months. Thus, long-lasting and durable superhydrophilic silicon has been obtained by using maskless, compact, and cost-effective nanosecond laser writing, without the need to employ any chemical post-processing. Potential applications of these surfaces include heat exchangers, biosensors, cell adhesives, and self-cleaning solar cells.