1. Effect of electric fields on silicon-based monolayers
- Author
-
Tiexin Li, Chandramalika Peiris, Essam M. Dief, Melanie MacGregor, Simone Ciampi, Nadim Darwish, Li, Tiexin, Peiris, Chandramalika, Dief, EM, MacGregor, Melanie, Ciampi, Simone, and Darwish, Nadim
- Subjects
monolayers ,surface reactions ,Electrochemistry ,charge transfer ,desorption ,General Materials Science ,bias voltage ,semiconductor junctions ,Surfaces and Interfaces ,Condensed Matter Physics ,Spectroscopy ,electrodes ,rate constants - Abstract
usc Refereed/Peer-reviewed Electric fields can induce bond breaking and bond forming, catalyze chemical reactions on surfaces, and change the structure of self-assembled monolayers on electrode surfaces. Here, we study the effect of electric fields supplied either by an electrochemical potential or by conducting atomic force microscopy (C-AFM) on Si-based monolayers. We report that typical monolayers on silicon undergo partial desorption followed by the oxidation of the underneath silicon at +1.5 V vs Ag/AgCl. The monolayer loses 28% of its surface coverage and 55% of its electron transfer rate constant (ket) when +1.5 V electrochemical potential is applied on the Si surface for 10 min. Similarly, a bias voltage of +5 V applied by C-AFM induces complete desorption of the monolayer at specific sites accompanied by an average oxide growth of 2.6 nm when the duration of the bias applied is 8 min. Current-voltage plots progressively change from rectifying, typical of metal-semiconductor junctions, to insulating as the oxide grows. These results define the stability of Si-based organic monolayers toward electric fields and have implication in the design of silicon-based monolayers, molecular electronics devices, and on the interpretation of charge-transfer kinetics across them. more...
- Published
- 2022