铅在铜上电沉积的原位椭圆偏振法

In-situ Ellipsometric Study of Lead Electrodeposition on Polycrystalline Cu

采用循环伏安法(CV)和原位椭圆偏振法(SE)研究铅在铜电极上的电沉积行为。原位椭圆偏振参数Ψ和Δ值的变化率在CV图峰电位处同时出现极值。通过建立单层膜模型描述"电极-溶液"界面的结构并对椭圆偏振光谱数据进行拟合得到铅沉积层厚度随电位的变化规律。拟合结果显示,铅在铜电极上的电沉积有3个不同的沉积速率,-0.20～-0.35V之间沉积速率为0.003nm/mV,-0.35～-0.48V之间沉积速率为0.025nm/mV,-0.48～-0.60V之间沉积速率为0.116nm/mV,由此表明铅的电沉积分为3个不同阶段:欠电位沉积阶段、欠电位沉积向本体沉积的过渡阶段和本体沉积阶段。

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.