Positioning of self-assembled, single-crystal, germanium islands by silicon nanoimprinting

Strain energy from the lattice mismatch of a heteroepitaxial system can create "self-assembled," single-crystal islands irregularly arranged on the surface. Alternatively, features of tens of nanometers can be patterned on a substrate by "nanoimprinting" using a mold and etching. When these two techniques are combined, the small patterned features can interact with the self-assembly process, causing the islands to form at the patterned features. The resulting regular array of very small islands may be useful for future devices. The positioning of single-crystal Ge islands by Si mesas formed by nanoimprinting and etching is demonstrated in this letter.