Dresden 2009 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 5: Nanostructures at surfaces: Wires, tubes

O 5.2: Vortrag

Montag, 23. März 2009, 11:30–11:45, SCH A215

High temperature growth of Ag-nanowires on bare Si(001) — •Simon Sindermann, Dirk Wall, Michael Horn-von Hoegen, and Frank-Joachim Meyer zu Heringdorf — Department of Physics and Center for Nanointegration Duisburg-Essen

Self-organized Ag-islands on bare Si(001) grow in various shapes. Amongst others, quasi 1-dimensional nanowires can be observed with a fixed width of a few hundred nanometers while their length can expand up to tens of micrometers. To specify the conditions and processes leading to nanowire-formation, the growth was examined at elevated temperatures (800K - 1000K) by Photo-Emission Electron Microscopy (PEEM). From the experimental data we determined the ratio of the number of nanowires over the number of all other islands and observed that this ratio increases exponentially with an activation energy of about 1.4eV [1]. Another important parameter to nanowire-growth is the vicinality of the surface. On 4^∘ vicinal samples all nanowires are aligned along the step edges in [110] direction, whereas we find nanowire in two directions ([110] and [110]) on flat Si(001). Due to previous experimental results, this observation can be explained by the anisotropy of diffusion which increases quickly from 0^∘ to reach the maximum at 4^∘ [2].

[1] D. Wall, S. Sindermann, M. Horn-von Hoegen, and F.-J. Meyer zu Heringdorf; J. P.:Cond. Matt. (submitted)

[2] D. Wall, K. R. Roos, M. Horn-von Hoegen, and F.-J. Meyer zu Heringdorf; Mater. Res. Soc. Symp. Proc. 1088E; 1088-W05-04 (2008)