The gold electrodes were self-assembled with L-cysteine and dodecanethiol, respectively. Using potassium ferricyanide as an electron transfer probe, the electrochemical behavior of the resulting monolayers on the gold electrode surface was investigated. Experimental results showed that the electrode with L-cysteine self-assembled monolayers should be very stable and dense, which failed to block the electron transfer (ET) between the gold electrode and potassium ferricyanide while the dodecanethiol modified gold electrode could inhibit that ET process effectively. Surface enhanced Raman scattering spectroscopic observations confirmed the stability and compact feature of L-cysteine monolayers using dodecanethiol as a probe for detecting the defects.

Key words: L-cysteine, self-assembly, electrochemistry, Raman scattering spectroscopy