Self-assembled molecular corrals on a semiconductor surface

Nano-corrals for capturing surface electrons are of interest in Molecular electronics. Here we show that haloalkane molecules, e.g., 1-chlorododecane, physisorbed on Si(111)-(7 x 7) self-assemble to form climers stable to 100 degrees C which corral silicon adatoms. Corral size is shown to be governed by the haloalkane chain-length. Spectroscopic and theoretical evidence shows that the haloalkane dimer induces electron transfer to the corralled adatom, shifting its energy levels by similar to 1 eV. Isolation of a labile pre-cursor points to a model for corral formation which combines mobility with immobility; monomers diffusing in a mobile vertical state meet and convert to the immobile horizontal dimers constituting the corrals. (c) 2006 Elsevier B.V. All rights reserved.