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Open Access Nano Express

The Influence of an Adsorbate Layer on Adatom Diffusion and Island Nucleation: Fe on Si(111)-√3 x √3-Au

K Paredis*, D Smeets and A Vantomme

Author Affiliations

Instituut voor Kern- en Stralingsfysica and INPAC, K. U. Leuven, Celestijnenlaan 200D, 3001, Leuven, Belgium

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Nanoscale Research Letters 2009, 4:1447-1451  doi:10.1007/s11671-009-9418-3

Published: 26 August 2009

Abstract

Using scanning tunneling microscopy, the influence of a thin Au layer on the diffusion of Fe adatoms and the subsequent island nucleation on a Si(111) surface is investigated. The adsorbate induces thestructure that increases the surface mobility of subsequently deposited Fe atoms, resulting in the formation well-defined nanoclusters. Surprisingly, the domain walls—inherent to the reconstruction—do not influence the surface diffusion, which demonstrates that the passivation is of much more importance for the self-assembly than the surface corrugation. Using the decoupling of the diffusion and nucleationonthe surface and the reactionwiththe surface and conventional nucleation theory, the activation energy for surface diffusionEd = 0.61 eV and the critical cluster sizei = 3 are determined, which reveal the microscopic details of the diffusion and nucleation processes.

Keywords:
Self-assembly; Surface reconstruction; Diffusion; Passivation; STM; Nanostructures; Iron silicide