Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9594565 | Surface Science | 2005 | 8 Pages |
Abstract
The functionalization of silicon surfaces with organic monolayers, bound through Si-C bonds, is an area of wide interest due to the technological promise of organosilicon hybrid devices, but also to investigate fundamental surface reactivity. In this paper, the use of alkylammonium and alkylphosphonium cations as sources of organic moieties to bind to hydrogen-terminated flat and porous silicon is demonstrated. Tetraalkylammonium, tetraalkyl/arylphosphonium reagents, and alkyl pyridinium salts can be utilized, but trialkylammonium salts cannot as they yield substantial surface oxidation. Under electrochemical conditions, either potentiostatic or galvanostatic modes, alkyl groups derived from the ammonium or phosphonium salts are grafted to the silicon surface and are bound through Si-C bonds. Covalent attachment of the organic monolayers to the surface was demonstrated by XPS, AFM scribing, and FTIR. The mechanism may proceed via reduction of the ammonium salt yielding alkyl radicals, R, which may be reduced to Râ and attack surface Si-Si bonds, leading to Si-C bonds, or the formation of silyl anions (â¡Siâ) under the cathodic conditions followed by nucleophilic attack on the trialkylammonium cation.
Keywords
Related Topics
Physical Sciences and Engineering
Chemistry
Physical and Theoretical Chemistry
Authors
Dong Wang, Jillian M. Buriak,