Black silicon photovoltaics

This article presents an overview of the fabrication methods of black silicon, their resulting morphologies, and a quantitative comparison of their optoelectronic properties. To perform this quantitative comparison, different groups working on black silicon solar cells have cooperated for this study. The optical absorption and the minority carrier lifetime are used as benchmark parameters. The differences in the fabrication processes plasma etching, chemical etching, or laser processing are discussed and compared with numerical models. Guidelines to optimize the relevant physical parameters, such as the correlation length, optimal height of the nanostructures, and the surface defect densities for optoelectronic applications are given. Black Silicon is a class of sub-micrometer stochatistically structured silicon surface with extremely high optical absorbtion. The optoelectronic properties of black silicon fabricated by different methods are reviewed and guidelines to optimize the relevant physical parameters are given.