Abstract: A method for producing periodic crystalline silicon nanostructures of large surface area by: generating a periodic structure having a lattice constant of between 100 nm and 2 ?m on a substrate, the substrate used being a material which is stable at up to at least 570° C., and the structure being produced with periodically repeating shallow and steep areas/flanks, and, subsequently, depositing silicon by directed deposition onto the periodically structured substrate, with a thickness in the range from 0.2 to 3 times the lattice constant, or 40 nm to 6 ?m, at a substrate temperature of up to 400° C., followed by thermally treating the deposited Si layer to effect solid-phase crystallization, at temperatures between 570° C. and 1400° C., over a few minutes up to several days, and optionally subsequently wet-chemically selective etching to remove resultant porous regions of the Si layer.