Berlin 2005 – scientific programme

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O: Oberflächenphysik

O 39: Nanostrukturen IV

O 39.1: Talk

Tuesday, March 8, 2005, 10:45–11:00, TU EB420

Formation and decay of Si/Ge nanostructures at the atomic level — •Bert Voigtländer, Neelima Paul, Vasily Cherepanov, and Josef Mysliveček — Institut für Schichten und Grenzflächen (ISG 3) and cni - Center of Nanoelectronic Systems for Information Technology, Forschungszentrum Jülich, 52425 Jülich, Germany

The step-flow growth mode is used to fabricate two-dimensional Si and Ge nanowires with a width of ≈3.5 nm and a thickness of one atomic layer (0.3 nm) by self-assembly on a Si(111) surface. Alternating deposition of Ge and Si results in the formation of a nanowire superlattice covering the whole surface. Also different kinds of two-dimensional Si/Ge nanostructures like alternating Si and Ge nanodots and nanorings having a width of 5-10 nm were grown. One atomic layer of Bi terminating the surface is used to prevent intermixing between Si and Ge and to distinguish between these elements. A difference in apparent height is measured in scanning tunneling microscopy (STM) images for Si and Ge, respectively. The method to distinguish between Si and Ge allows to study intermixing on the nanoscale and to identify the fundamental diffusion processes giving rise to the intermixing.