Methods for preparing a substrate surface are provided, for purposes including manufacturing a low reflectivity surface. In some aspects, the methods include providing a material comprising an etching mask on a substrate, subjecting the material to a first isotropic etching phase, and subjecting the material to a first anisotropic etching phase, thereby forming a textured surface on the material, wherein the textured surface comprises structures with dimensions in a sub-micron range.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH
 This invention was made with government support under 1041895 awarded from the National Science Foundation and the Department of Energy. The United States government has certain rights in the invention.