Abstract:

Electrodeposition of Pb on polycrystalline Cu surfaces has been investigated by cyclic voltammetry(CV) and in-situ spectroscopic ellipsometry(SE). The ellipsometric parameters Ψ and Δ peak corresponded to both underpotential deposition(UPD) and bulk deposition peak potentials. The “substrate-solution” interface structure was described with a single-layer model, (substrate Cu-deposition Pb layer) and the thicknesses of Pb layer for different scan potentials were obtained by fitting experimental data with the model. Fitting results showed that Pb electrodeposition on the Cu electrode was with three different deposition rates, -0.20~-0.35 V, 0.003 nm/mV; -0.35~-0.48V, 0.025 nm/mV; -0.48~-0.60 V, 0.116 nm/mV. Based on the fitting results, three stages, which were formation of UPD layer, transitional period between the UPD and bulk deposition and formation of bulk deposition layer were proposed for the electrodeposition process of copper in the Pb2+ solution.

Key words: In-situ spectroscopic ellipsometry, Lead electrodeposition, Copper