Berlin 2012 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 42: Nanostructures at surfaces I
O 42.9: Vortrag
Mittwoch, 28. März 2012, 12:30–12:45, MA 042
Quasi-1D metallic Ag-wires grown on vicinal Silicon surfaces — •Christian Brand, Jȩdrzej Schmeidel, Christoph Tegenkamp, and Herbert Pfnür — Institut für Festkörperphysik, Leibniz Universität Hannover, Germany
A prototype system of a nearly free 2D electron gas system is the Ag-(√3 × √3) reconstruction on a Si(111)-(7 × 7) surface. Consequently, a promising route to fabricate a 1D electron gas system might be the self assembly of Ag wetting structures on uniaxial Si(557) surfaces.
The Si(557) surface consists of (111) terraces and triple steps with a periodicity of 5.73 nm. By adsorption of sub-monolayer amounts of Ag at 770 K several types of quasi-1D structures are formed, accompanied by locally varying refacetting of the surface. Besides insulating chains of monatomic width (α-, β- and γ-type) also metallic wires with (√3 × √3) reconstruction are formed, as deduced from our LEED- and STM/STS-study.
In many cases metallic monolayer species are decoupled electronically from the Si-surfaces by forming Schottky barriers, which limit the applicability of STS to measure the electronic structure of the wires themselves at low bias voltages. In order to contact the wires electrically, a shadow mask technique on the basis of a Si3N4 membrane has been developed. First results will be presented.