GaAs electrodes coated with hydrophobic, methyl-mercaptobiphenyl (CH 3-MBP) monolayers exhibited an excellent electrochemical stability. We found that the interface resistance of the chemically functionalized GaAs shows linear relationships with electrolyte pH and bias potential in a reproducible manner. The impedance spectra measured in a wide frequency range (f = 100 kHz to 50 mHz) are analyzed with several equivalent circuit models in a quantitative manner, and the pH sensitivity extrapolated from two linear relationships (35 mV pH-1) can be attributed to the absorption of the OH- ions on the hydrophobic surface.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films