Since graphene, a single layer of graphite, was produced in 2004, scores of other 2D materials called van der Waals materials have been identified. The potential of these layered crystalline semiconductors for computational logic, photovoltaics, and other areas is great, but the challenge in handling the materials, determining their inherent characteristics and how they act when put in few-layer form is an impediment to their use.
Typically, researchers want to determine the crystal orientation and anisotropic resistivity of a small flake of material. In anisotropic materials, the crystal structure is different along the X and Y directions and therefore it conducts electricity differently in one direction than the other. The Northwestern investigators found used conformal mapping and a slew of other data analysis methods to determined not only the crystal orientation but also its effects on resistivity from a small number of experimental measurements.