High aspect ratio nanoneedle probes with an integrated electrode at the tip apex

Abstract

Many nanoscale characterization techniques require high aspect ratio nanoneedle probes with an integrated electrode that is electrically insulated everywhere except at the tip apex. We report the utilization of electron beam induced deposition, focused ion beam milling, and atomic layer deposition to fabricate such probes at the sub-100 nm length scale. This fabrication method is highly reproducible and enables precise control of the probe dimensions. Subsequent electrodeposition at the integrated electrode enables customized functionalization of the tip apex. These probes have clear applications in scanning electrochemical microscopy-atomic force microscopy, magnetic force microscopy, apertureless near-field optical microscopy, and tip-enhanced Raman spectroscopy.