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

Abstract

The application of imaging techniques based on ensembles of nitrogen-vacancy (N-V) sensors in diamond to characterize electrical devices has been proposed, but the compatibility of N-V sensing with operational gated devices remains largely unexplored. Here we report the fabrication of graphene fieldeffect transistors directly on the diamond surface and their characterization by N-V microscopy. The current density within the gated graphene is reconstructed from N-V-magnetometry measurements under both mostly p- and n-type doping, but the exact doping level is found to be affected by the measurements. Additionally, we observe a surprisingly large modulation of the electric field at the diamond..