Rod-shaped or cylindrical structures in the nm range on a substrate of silicon are manufactured. A first cylinder of silicon is selectively epitaxially deposited in the hole of a mask layer of oxide, and the mask layer is removed. The silicon is then oxidized to form an oxide layer having such a thickness that a thinner, second cylinder of silicon having practically the same height as the first cylinder remains. In a last step, this oxide layer is removed, so that the second cylinder forms a freestanding silicon rod on the surface of the substrate.