Berlin 2005 – wissenschaftliches Programm

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O: Oberflächenphysik

O 4: Epitaxie und Wachstum I

O 4.5: Vortrag

Freitag, 4. März 2005, 11:45–12:00, TU EB202

Growth of Copper on Nickel (111) - a Scanning Tunneling Microscopy Study — •Florian Maier, Reinhard Lindner, and Hans-Peter Steinrück — Lehrstuhl Physikalische Chemie II, Universität Erlangen-Nürnberg, Egerlandstr. 3, D-91058 Erlangen

Controlled growth of bimetallic structures on a nanometer scale is of crucial interest in many fields. Therefore, the initial growth stage of copper on Ni(111) (0.05 ML < θ _Cu < 1.5 ML) as a model system was studied with scanning tunneling microscopy (STM). Copper was deposited using an electron beam evaporator that produced a flux of neutral atoms accompanied by a small fraction of ions. The latter was controlled by a countervoltage. The island size distribution was investigated as a function of substrate temperature (100 K or room temperature), concomitant copper ions, preadsorbed layers of water, and preadsorbed carbon monoxide.

In summary, room temperature promotes two-dimensional growth (due to kinetic effects), ion assisted deposition yields small islands (due to enhanced nucleation center formation), deposition on preadsorbed water layers results in a morphologie analogous to Stranski-Krastanov growth (due to No-dqsoft landingNo-dq of preformed copper clusters), and CO coadsorbtion prohibits island fusion (due to reduced diffusion length and/or step stabilisation).