Charge Transfer vs Mass Transfer Mechanism in Electrodeposition of Copper thin films: A Structural Exploration

Abstract

Nucleation and growth mechanism can be classified into mass or diffusion controlled and charge or interfacial controlled. In mass control, the growth is limited by the rate at which the material is transported through the solution to the electrode surface, while in charge control the growth rate is limited by the rapidity with which the ions are incorporated into the new phase. In this project, Cu thin films have been synthesized on graphite substrate using electrodeposition technique which occurs by a process of nucleation and growth. The deposition of Copper thin films on the rough face of the graphite substrate is performed with two different solutions – a mass controlled one (with Na2SO4), and a charge controlled one (without Na2SO4). The analysis of the corresponding potentiostatic j/t transients suggests a deposition according to 3D instantaneous nucleation. Further, a structural exploration was done into the deposition structure using AFM and SEM technique differentiating the deposition quality via grain based properties.