Nanosculpting of complex oxides by massive ionic transfer

Scanning probe microscopy (SPM)-based approaches have been extensively studied as methods to control the structure and properties of materials on the nanoscale. In many cases, the SPM probe is physically utilized to control structure and properties. In addition to physical modulation, it has been reported that voltage can be effectively used to modulate electrochemical phenomena on the sample surface. These studies suggest that electrochemical modulation of the structure and properties is possible by applying a voltage. Herein, in order to demonstrate voltage induced modulation of surface structure, we explored surface nanosculpting by creating electrochemically induced pits on the surface of TiO₂ thin films through the application of voltage using the atomic force microscope tip. Using a unipolar negative voltage sweep, pits were successfully generated. Further, the electric potential distribution was simulated to unravel the relationship between the pit volume and the magnitude of the applied voltage. Finally, surface protrusion induced by positive voltage sweep was also observed to elucidate the complete process of electrochemically induced surface modulation. These results can offer fundamental information for understanding how surface structure can be modulated by electrochemical phenomena.