Characterizing carrier transport in nanostructured materials by force-resolved microprobing

The advent of novel nanostructured materials has enabled wearable and 3D electronics. Unfortunately, their characterization represents new challenges that are not encountered in conventional electronic materials, such as limited mechanical strength, complex morphology and variability of properties. We here demonstrate that force-resolved measurements can overcome these issues and open up routes for new applications. First, the contact resistance to 2D materials was found to be sensitively depending on the contact force and, by optimizing this parameter, reliable contacts could be repeatably formed without damage to the fragile material. Moreover, resistance of three-dimensional surfaces could be investigated with high accuracy in spatial position and signal through a force-feedback scheme. This force-feedback approach furthermore permitted large-scale statistical characterization of mobility and doping of 2D materials in a desktop-sized automatic probing system that fits into glove boxes and vacuum enclosures using easily available and low-cost components. Finally, force-sensitive measurements enable characterization of complex electronic properties with high lateral resolution. To illustrate this ability, the spatial variation of a surface’s electrochemical response was investigated by scanning a single electrolyte drop across the sample.