Real time monitoring of electrochemical deposition of tellurium on Au(111) electrode by optical second harmonic generation technique

Abstract

Electrochemical deposition of Te on a single crystal Au(111) electrode was monitored by the optical second harmonic generation (SHG) technique. The rotational anisotropic SHG measurement was used to estimate the overall symmetry of the electrode surface during the first underpotential deposition (upd), the second upd and bulk deposition of Te in real time. The formation of the first Te upd layer seemed to proceed in two steps as the SH rotational anisotropy became rather isotropic in the middle of the first upd and, then, the anisotropic character of the surface recovered again after the completion of the first upd. The experimental results suggest random deposition in the initial stage followed by the island growth, leading to the highly ordered ( 3 × 3 ) R30° structure. It was also found that the anisotropic character of the overall surface symmetry was attenuated after the second upd and bulk deposition of Te.