Surface plasmons interference nanogratings: wafer-scale laser direct structuring in seconds

It is always a great challenge to bridge the nano- and macro-worlds in nanoscience, for instance, manufacturing uniform nanogratings on a whole wafer in seconds instead of hours even days. Here, we demonstrate a single-step while extremely high-throughput femtosecond laser scanning technique to obtain wafer-scale, highly regular nanogratings on semiconductor-on-metal thin films. Our technique takes advantage of long-range surface plasmons-laser interference, which is regulated by a self-initiated seed. By controlling the scanning speed, two types of nanogratings are readily manufactured, which are produced by either oxidation or ablation. We achieve a record manufacturing speed (>1 cm(2) s(-1)), with tunable periodicity of ? < 1 mu m. The fractional variation of their periodicity is evaluated to be as low as increment ?/? approximate to 0.5%. Furthermore, by utilizing the semiconductor-on-metal film-endowed interference effects, an extremely high energy efficiency is achieved via suppressing light reflection during femtosecond laser nano-processing. As the fabricated nanogratings exhibit multi-functionality, we exemplify their practical applications in highly sensitive refractive index sensing, vivid structural colors, and durable superhydrophilicity.

Automated summary

This study demonstrates an efficient femtosecond laser scanning technique for manufacturing highly regular nanogratings on semiconductor-on-metal thin films. The technique enables high-speed manufacturing with tunable periodicity. The interference effects of the semiconductor-on-metal film also contribute to high energy efficiency during laser nano-processing. The fabricated nanogratings have various applications in refractive index sensing, structural colors, and superhydrophilicity.