Proton doping of graphene FETs enabled by ionic modulation from polysilazane dielectrics

Abstract

Graphene field-effect transistors offer great potential for next-generation electronics due to graphene's high carrier mobility and atomic-scale thickness. However, stable device operation requires precise control of the dielectric interface, which impacts carrier transport and doping. In this study, we use solution-processed polysilazane (PSZ)-derived dielectrics as both gate insulators and active ionic environments for modulating graphene's electronic properties. The PSZ films, processed under humid conditions, generate hydroxyl-rich surfaces that serve as proton reservoirs. Electrical characterization and in-situ Raman spectroscopy show that gate bias induces proton doping of graphene, manifesting as hysteresis, Dirac point shifts, and D-band enhancement arising from phonon activation and interfacial Coulombic perturbations. The device also exhibits characteristic doping and relaxation times, revealing proton migration dynamics. Our findings suggest that PSZ dielectrics provide both gate insulation and dynamic electrochemical modulation of the graphene channel, offering a new strategy for dielectric interface engineering in 2D electronic devices.