Gallium Nitride Nanowire Probe for Near-Field Scanning Microwave Microscopy
Joel C. Weber, Paul T. Blanchard, Aric W. Sanders, Atif A. Imtiaz, Thomas M. Wallis, Kevin J. Coakley, Kristine A. Bertness, Pavel Kabos, Norman A. Sanford, Victor M. Bright
We report on the fabrication of a GaN nanowire probe for near-field scanning microwave microscopy. A single nanowire was Pt-bonded to a commercial Si cantilever prior to evaporation of a Ti/Al coating to provide a microwave signal pathway. Testing over a microcapacitor calibration sample shows the probe to have capacitance resolution of at least 0.7 fF with improved sensitivity and reduced uncertainty compared with a commercial microwave probe. High strength of the defect-free nanowire enabled it to maintain a tip radius of 150 nm after multiple contact-mode scans while demonstrating nanometer-scale topographical resolution.