Fabrication of Ge nanoclusters on Si with a buffer layer-assisted growth method

Size selectable Ge nanoclusters are formed on Si using a buffer layer-assisted growth method. A condensed inert gas layer of xenon, with low surface free energy, was used as a buffer to prevent direct interactions of deposited Ge atoms with Si substrates during Ge nanocluster growth. The scanning tunneling microscope studies indicate absence of a strained wetting layer between Ge nanoclusters. These nanoclusters are substantially smaller and denser than the Ge hut clusters that are formed with the normal Stranski–Krastanov growth mode. The morphology of the nanoclusters can be tuned over a wide range, which is very desirable for studying the three-dimensional confinement effect.