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. (C) 2003 Elsevier B.V. All rights reserved.