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MM: Metall- und Materialphysik

MM 40: Nanostructured Materials III

MM 40.4: Vortrag

Freitag, 31. März 2006, 11:45–12:00, IFW D

Structure and conductance in metal nanosystems — •Tammo Block¹, Jan Rönspies¹, Svend Vagt¹, Volkmar Zielasek², and Herbert Pfnür¹ — ¹Institut für Festkörperphysik, Universität Hannover — ²Institut für Angewandte und Physikalische Chemie, Universität Bremen
Recently the Pb/Si(557) system has been demonstrated to exhibit a high quasi one-dimensional conductance along the Si(557) step direction on a macroscopic scale, associated with a metal-semiconductor phase transition [1]. Here we describe how to bring this system one step further, by using a lithographical method to perform measurements on only a few of these wires selected out of the ’wire array’ of the Pb/Si(557) system. We employ electron-beam stimulated thermal desorption of oxygen (EBSTD) in UHV from ultrathin SiO₂ layers on a Si(557) surface to generate windows of clean Si in a SiO₂ mask, usually in the form of narrow (≤20nm) lines along the 557-step direction. Subsequent deposition of Pb and annealing to 640 K forms the 1D conducting system descibed above. TiSi contacts, produced previously ex-situ with conventional e-beam lithography, and the tip of a STM are used to connect these wires for conductivity measurements.The influence of various kinds of defects on electrical transport in the structures will be discussed.

[1] PRL 95 (2005) 176804