Bitmap-assisted focused ion beam fabrication of combined atomic force scanning electrochemical Microscopy probes

Bitmap assisted focused-ion-beam (FIB) milling for the fabrication of combined atomic force scanning electrochemical microscopy (AFM-SECM) probes is presented. This technique facilitates the integration of frame-shaped nanoelectrodes recessed from the AFM tip. Thereby, the fabrication process for bifunctional AFM-SECM tips is significantly simplified while maintaining high reproducibility with reduced FIB milling time/cost. Additionally, different electrode geometries (frame- and disk-shaped) and a wide variety of ratios between electrode size and re-shaped AFM tip length can be easily maintained. Disk nanoelectrodes can be integrated with radii down to 50 nm after appropriate pre-modification of the AFM tip. Characterization and performance of bifunctional probes are demonstrated by using cyclic voltammetry at the tip-integrated electrodes and simultaneous imaging in contact mode AFM and feedback-mode SECM operation.