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O: Oberflächenphysik

O 22: Nanostrukturen

O 22.10: Vortrag

Mittwoch, 24. März 1999, 16:45–17:00, S1

Selective adsorption of organic molecules on nano-patterned silicon — •H. Rauscher¹, T. A. Jung², A. Kirakosian¹, J.-L. Lin¹, K. Müllen³, and F. J. Himpsel¹ — ¹Physics Department, Univ. of Wisconsin-Madison, USA — ²Paul-Scherrer-Institute, Switzerland — ³Max-Planck-Institute for Polymer Research, Germany

In search of a method for fabrication of tailored one-dimensional

nanostructures we have studied the selective adsorption of

3,10-di(propyl)perylene (DPP) molecules on nano-patterned Si(111)

surfaces with a self-organized calcium fluoride overlayer as

mask. These molecules exhibit distinct reactivities with the

initial overlayer (CaF₁) and the second overlayer

(CaF₂). Scanning tunneling microscopy shows that reactivity

of DPP is much higher on CaF₁ as compared to CaF₂.

The molecules can be adsorbed preferentially on CaF₁

nanostripes produced by self-assembly on stepped Si(111).

This produces large arrays of parallel molecular nanowires with

a width in the 1-15 nm range. We discuss the selectivity in

terms of a mechanism where the HOMO and LUMO of the molecule

interact with the valence band and conduction band of CaF₁

and CaF₂, determined directly by scanning tunneling

spectroscopy.

Supported by NSF under Award Nos. DMR-9624753 and DMR-9632527.