Application of the electrochemical quartz crystal microbalance technique to copper sonoelectrochemistry

The applicability of the electrochemical quartz crystal microbalance technique in an ultrasonic field created by an ultrasound probe is demonstrated for the electrodeposition of copper. Cyclic voltammetry and potentiostatic depositions in acidic sulfate-based copper electrolytes were performed at different ultrasonic intensities. The electrochemical quartz crystal microbalance was operated in ultrasonic fields with intensities up to 30 W cm^-2. For cyclic voltammetry, potential resolved and averaged (apparent) current efficiencies were calculated from mass and charge data in function of the amplitude of the ultrasonic horn. Ultrasound slightly affected the current efficiencies during copper deposition in cyclic voltammetry, but did not change the efficiencies during dissolution. During potentiostatic depositions the current efficiency increased from 84% to almost 100% upon application of ultrasound. Morphology of deposits prepared by potentiostatic depositions was analyzed by scanning electron microscopy, and found to be different at high ultrasonic intensities