Multiparametric electrochemical characterisation of Te–Cu–Pb atomic three-layer structure deposition on polycrystalline gold

Successive underpotential deposition of Tead, Cuad and Pbad adlayers in the potentiodynamic mode was used for Tead/Cuad/Pbad atomic three-layer structure assembling on polycrystalline Au support. Layer-by-layer deposition was characterised in each of the stages with potentiodynamic electrochemical impedance spectroscopy (PDEIS) by variations, with the electrode potential E, of double layer pseudocapacitance Qdl, charge transfer resistance Rct and Warburg coefficient A of diffusion impedance. Qdl(E) has shown a strong decrease in the cathodic scan during Te atomic layer deposition on Au, a sharp peak in the subsequent Cuad deposition on Au/Tead and an increase in Pbad deposition on Au/Tead/Cuad. The inverses of charge transfer resistance and Warburg coefficient have shown characteristic maxima in Rct-1(E) and A−1(E) dependencies in all the three stages of Tead/Cuad/Pbad three-layer assembling. The characteristic features in the dependences on the potential of the ac response parameters compensated for insufficient self-descriptiveness of the dc part of the nonstationary interface response in the layer-by-layer deposition. High information density of PDEIS spectra provides better control of electrochemical processes on nonstationary interfaces and this new opportunity can enable wider use of electrochemical approaches for thin-layer structures preparation.