Morphology and magneto-transport in exfoliated graphene on ultrathin crystalline b{eta}-Si3N4(0001)/Si(111)

We report the first experimental study of graphene transferred on \b{eta}-Si3N4(0001)/Si(111). Our work provides a comprehensive quantitative understanding of the physics of ultrathin Si3N4 as a gate dielectric for graphene-based devices. The Si3N4 film was grown on Si(111) under ultra-high vacuum (UHV) conditions and investigated by scanning tunneling microscopy (STM). Subsequently, a graphene flake was deposited on top of it by a polymer-based transfer technique, and a Hall bar device was fabricated from the graphene flake. STM was employed again to study the graphene flake under UHV conditions after device fabrication and showed that surface quality is preserved. Electrical transport measurements, carried out at low temperature in magnetic field, revealed back gate modulation of carrier type and density in the graphene channel and showed the occurrence of weak localization. Under these experimental conditions, no leakage current between back gate and graphene channel was detected.