Investigations on black silicon nanostructures fabricated by reactive ion etching on highly curved surfaces

A large amount of valuable research on black silicon (b-Si) nanostructures has pushed its use further into application in recent years. However, the research results to be found are all related to plane substrates. For an investigation of b-Si structures on curved surfaces, they were fabricated on hemispherical silicon lenses using inductively coupled plasma reactive ion etching. It was possible to achieve different structure morphologies according to the selected etching parameters, analogous to their fabrication on Si wafers. Scanning electron microscopy inspections of the structure morphology were carried out to study the homogeneity across the lens surface as well as the orientation of the structures. Simulations of the bent electric field within the etching chamber and the resulting ion trajectories explain the underlying etching process that creates structures approximately perpendicular to the curved lens surface. Optical reflectance measurements confirm the findings on homogeneity and orientation.

Automated summary

Valuable research on black silicon (b-Si) nanostructures has led to its increased application. However, existing research focuses on flat substrates. This study investigated b-Si structures on curved surfaces by fabricating them on hemispherical silicon lenses using inductively coupled plasma reactive ion etching. Different structure morphologies were achieved based on the etching parameters selected, similar to fabrication on Si wafers. Scanning electron microscopy inspections confirmed the homogeneity and orientation of the structures, while simulations explained the underlying etching process.