Self-induced current oscillations during anodization of Ti in LA containing DMSO electrolyte

• Regular, self-induced current oscillations (COs) appear during nanotube growth.
• COs depend on electrolyte (lactic acid amount) and anodization conditions.
• COs lead to the growth of regular self-stacked multilayer nanostructures.
• Surface roughness and stirring (diffusion) influence the COs characteristics.

During self-organized nanotubular oxide growth by electrochemical anodization of Ti in lactic acid (LA) containing dimethyl sulfoxide (DMSO) electrolytes, we observe the occurrence of regular current oscillations (COs). Key factors that influence COs are the LA concentration, the surface roughness and diffusion limitation. The oscillation characteristics (amplitude and period) depend on both LA concentration and applied voltage. Under optimized oscillation conditions a sequential growth/detachment of the TiO2 layers is observed that leads to a self-stacking of TiO2 nanostructured multilayers.