The Properties of Electrochemically-Grown Copper Sulfide Films

The electrochemical growth of copper sulfide films on copper has been studied voltammetrically and potentiostatically in 0.1 M sodium chloride solutions containing sulfide concentrations ranging from 10(-4) M to 10(-3) M. The properties of the films formed were investigated using electrochemical impedance spectroscopy. Film growth was observed to occur in two stages: the initial formation of a thin porous base layer at low potentials, followed by film restructuring leading to increased porosity and the deposition of an outer copper sulfide layer at more positive potentials. At more oxidizing potentials the overall film growth rate was determined by the properties of the outer deposit, not by the formation of a passive barrier layer at the Cu/film interface