the State Major Program for Scientific Instrument Development of China(2011YQ03012406);Innovation Group ofInterfacial Electrochemistry, China(21321062);National Natural Science Foundation of China(21373172)
State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, Fujian Province, P. R. China
Abstract:
Cyclic voltammetry and chronoamperometry have been used to investigate the mechanism of gold electrodeposition on the n-Si(111) electrode surface from a citrate bath, which had successfully applied to directly electroplate a dense gold film on the silicon surface. The results show that Au electrodeposition on the n-type silicon surface is an irreversible process, and the nucleation overpotential reaches 250 mV. According to Cottrell equation, the diffusion coefficient (D) is calculated to be (1.81 ± 0.14) × 10-4 cm2·s-1. The Scharifker-Hills (SH) model was used to analyze the experimental data. Agreement between the fitting curves and the theoretical curves confirms that the nucleation process of Au electrodeposition on the n-type silicon surface follows the progressive nucleation mechanism with three-dimensional growth under diffusion control. To further confirm the progressive nucleation mechanism, scanning electron microscopy (SEM) was used to observe the nucleation and growth of Au deposits at the initial stage of electrodeposition. The SEM results show that the morphology and density of the Au deposits are affected by the electrochemical deposition potential and time.
