Formation and electrical characterization of directed self-assembled Ge/Si quantum dot

Directed self-assembly of sub-10 nm Ge islands is a candidate for producing laterally coupled quantum dot molecules with geometrically-defined spin exchange couplings. The islands are created by the nucleation of Ge islands on nanoscale SiC templates defined by direct-write electron-beam lithography.\footnote{O. Guise, J. Ahner, J. John T. Yates, V. Vaithyanathan, D. G.Schlom, J. Levy, Appl. Phys. Lett. 87, 1902 (2005).} Ge islands are coupled through ohmic contacts to the Si capping layer, and geometries can be defined that are suitable for either vertical or lateral transport.We describe low-temperature magneto-transport measurements on individual and small arrays of Ge islands grown on semi-insulating silicon substrates.