Facile Charge-Displacement at Silicon Gives Spaced-out Reaction

Adsorbates on metals, but not previously on semiconductors, have been observed to display long-range repulsive interactions. On metals, due to efficient dissipation, the repulsions are weak, typically on the order of 5 meV at 10 Å. On the 7×7 reconstruction of the Si(111) surface, charge transport t...

Full description

Saved in:
Bibliographic Details
Published in:Journal of the American Chemical Society 2011-10, Vol.133 (41), p.16560-16565
Main Authors: Ebrahimi, Maryam, Huang, Kai, Lu, Xuekun, McNab, Iain R, Polanyi, John C, Waqar, Zafar, Yang, Jody (S. Y.), Lin, Haiping, Hofer, Werner A
Format: Article
Language:English
Subjects:
Adsorption
Bromobenzenes - chemistry
Ethylene Dibromide - chemistry
Hydrocarbons, Brominated - chemistry
Particle Size
Quantum Theory
Silicon - chemistry
Surface Properties
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Adsorbates on metals, but not previously on semiconductors, have been observed to display long-range repulsive interactions. On metals, due to efficient dissipation, the repulsions are weak, typically on the order of 5 meV at 10 Å. On the 7×7 reconstruction of the Si(111) surface, charge transport through the surface has been demonstrated by others using charge injection by STM tips. Here we show that for both physisorbed brominated molecules, and for chemisorbed Br-atoms, induced charge-transfer in the Si(111)-7×7 surface can lead to a strong repulsive interaction between adsorbates, calculated as 200 meV at 13.4 Å. This large repulsive interaction must be channeled through the surface since it causes widely spaced “one-per-corner-hole” patterns of physisorption (three casesdirectly observed here) and subsequent chemisorption (four cases observed). The patterns were observed by ultrahigh vacuum scanning tunneling microscopy for four different brominated hydrocarbon adsorbates; 1,2-dibromoethane, 1-bromopropane, 1-bromopentane, and bromobenzene, deposited individually on the surface. In every case, adsorbates were overwhelmingly more likely to be found singly than multiply adjacent to a corner-hole, constituting a distinctive pattern having a probability p = 7 × 10–5 compared to a random distribution.
ISSN:0002-7863
1520-5126
DOI:10.1021/ja205716t