Chemically anisotropic single-crystalline silicon nanotetrahedra

We describe a method based on silicon micromachining to machine single-crystalline silicon nanoparticles bounded by (111) faces in the form of tetrahedra. The technology allows the fabrication of tetrahedra in a size range from 20 to 1000 nm side length, and gives the possibility to chemically modify sites (faces, edges and/or tips) within certain limits. The chemical modification is anticipated to facilitate the self-assembly into new supermaterials such as photonic crystals in the diamond lattice.