High-accuracy etching of TiO₂ nanostructures for large-area metasurface concentrators

Le résumé fourni par la source

Metasurface-based solar concentrators offer significant potential to effectively capture broadband, wide-angle sunlight without an extra tracking system, making them a promising pathway for advanced solar energy utilization. Currently, how to mass-produce nanostructures on large-area surfaces is both a research hotspot and a technical challenge. Therefore, a manufacturing method has been proposed that utilizes nanoimprint lithography for mass-producing surface nanopatterns on concentrators, followed by etching techniques to transfer these patterns onto TiO₂ substrates. However, masks fabricated via nanoimprint lithography suffer from issues such as irregular shapes, weak adhesion between the mask and the substrate, and fragmentation during the etching process. Furthermore, the constraints imposed by the material properties of TiO₂ and the size inhomogeneity of nanopatterns mean that achieving large-area etching of nanopatterns with high aspect ratios and high uniformity remains a significant challenge. To address these challenges, this study proposes a method that employs reactive ion etching (RIE) technology incorporating sidewall protection and ion-assisted etching processes. This approach effectively resolves the issues of low etching rate and insufficient selectivity encountered in other etching methods. A 4-inch concentrator has been successfully fabricated, achieving high-aspect- ratio nanostructures with a maximum etching depth of 400 nm. Furthermore, the etched TiO₂ nanostructures can achieve sidewall angles exceeding 89°, even when the mask quality is imperfect. These results demonstrate that RIEbased processes enable high-efficiency, high-precision nanofabrication of metasurface concentrators.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.