Review of Silicon-Based Nanomaterials Fabricated via Laser Microstructuring, Electrochemical Etching, and Hybrid Microstructures: Exploring Functional Integration and Future Applications

This review examines silicon surfaces produced by femtosecond laser microstructuring and electrochemical etching, as well as their sequential integration. Laser processing creates multiscale topographies, including laser-induced periodic surface structures (LIPSS), conical features, and craters, whereas electrochemical etching generates porous silicon with tunable pore dimensions and high surface area. The central focus is the process coupling between these techniques: how laser-generated topography, defects, and modified surface chemistry may influence subsequent electrochemical dissolution, and how etching, in turn, may alter the stability and wetting of the laser-defined architecture. Available studies demonstrate substantial changes in morphology, roughness, and contact angle after sequential processing, but do not yet establish universal synergistic enhancement or self-cleaning performance. Accordingly, this review distinguishes experimentally demonstrated process-integration effects from mechanistic hypotheses and future design targets. It also evaluates evidence limitations related to durability, mechanical stability, scalability, reference accuracy, and application-specific validation, with particular attention to conceptual sensing platforms based on hierarchical silicon surfaces.