Imaging Graphene Field-Effect Transistors on Diamond Using Nitrogen-Vacancy Microscopy

Imaging techniques using nitrogen-vacancy centers in diamond are appealing for characterizing two-dimensional devices and materials, but their compatibility with gated devices is largely unexplored. This work uses wide-field N-V techniques to examine graphene field-effect transistors fabricated on the diamond's surface, and highlights some of the challenges in this approach. Current densities in the device are mapped at different doping conditions, and substantial modulation of the electric field at the diamond surface is seen, suggesting a complex electrostatic response of the multilayered structure. Pathways to mitigate the invasiveness of the imaging technique are discussed.