▎ 摘　　要

We report on top-gated field effect devices built from quasi-freestanding monolayer graphene (QFMLG) on 6H-SiC(0001) in combination with a silicon nitride (SiN) gate dielectric. SiN was grown by plasma enhanced chemical vapour deposition. The composition of the dielectric was investigated by x-ray photoelectron spectroscopy (XPS). Spectroscopic and electrical characterization of the graphene layers were done by XPS, Raman spectroscopy and Hall effect measurements before and after SiN deposition. In contrast to previous reports on SiN/graphene, we observe that our dielectric layer induces strong n-type doping. With such a gate insulator, the neutrality level of the QFMLG could be accessed by an appropriate gate voltage.