Nano Express

Nanoscale Research Letters

, 4:1447

First online:

Open Access This content is freely available online to anyone, anywhere at any time.

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

  • K ParedisAffiliated withInstituut voor Kern- en Stralingsfysica and INPAC, K. U. Leuven Email author 
  • , D SmeetsAffiliated withInstituut voor Kern- en Stralingsfysica and INPAC, K. U. Leuven
  • , A VantommeAffiliated withInstituut voor Kern- en Stralingsfysica and INPAC, K. U. Leuven

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 the http://static-content.springer.com/image/art%3A10.1007%2Fs11671-009-9418-3/MediaObjects/11671_2009_Article_9418_IEq1_HTML.gif structure that increases the surface mobility of subsequently deposited Fe atoms, resulting in the formation well-defined nanoclusters. Surprisingly, the domain walls—inherent to the http://static-content.springer.com/image/art%3A10.1007%2Fs11671-009-9418-3/MediaObjects/11671_2009_Article_9418_IEq2_HTML.gif 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 nucleationon the surface and the reactionwith the surface and conventional nucleation theory, the activation energy for surface diffusionE d = 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