Photoimprinting patterns of the Br-atoms at the Si (111) 7x7 surface

The CH₃Br molecules were deposited on the Si(111)-7x7 surface at 50K under vacuum conditions.

On the surface the adsorbed molecules undergo self-assembly and form rings,

which correspond to the structure of the Si(111)-7x7 surface.

Then the adsorbed molecules are irradiated with 193 nm laser radiation.

As a result, photodissociation of the adsorbates occurs. The newly formed CH₃ radical desorb to the gas phase,

while the Br-atoms reside on the surface and form covalent bonds with silicon.

These imprinted rings of the Br-atoms are stable at room temperature and can survive heating.

This work was published in: “Imprinting Br-atoms at Si (111) from a SAM of CH3Br(ad), with pattern retention”, S. Dobrin, X. Lu, F.Y. Naumkin, J.C. Polanyi, and Jody (S.Y.) Yang, Surface Science, 573 (2004) L363. This paper became a subject of a perspective paper by Professor R. Osgood, Columbia University, New York, and also has been cited by Chem. &. Eng. News .v. 82 (Nov.15, 2004), Number 46, p.8.

"Maskless nanopatterning and formation of nanocorrals and switches, for haloalkanes at Si(111)-7 × 7", S. Dobrin, K.R. Harikumar, T B Lim, L Leung, I.R. McNab, J.C. Polanyi, P.A. Sloan, Z. Waqar, J (S Y) Yang, S Ayissi, and W.A. Hofer, Nanotechnology, 18 (2007) 044012