Polarization-Dependent Electronic Transport in Graphene/Pb(Zr,Ti)O3 Ferroelectric Field-Effect Transistors

Ferroelectric field-effect transistors (FeFETs) employing graphene on inorganic perovskite substrates receive considerable attention due to their interesting electronic and memory properties. They are known to exhibit an unusual hysteresis of electronic transport that is not consistent with the ferroelectric polarization hysteresis and is previously shown to be associated with charge trapping at graphene-ferroelectric interface. Here, an electrical measurement scheme that minimizes the effect of charge traps and reveals the polarization-dependent hysteresis of electronic transport in graphene-Pb(Zr,Ti)O-3 FeFETs is demonstrated. Observation of the polarization-dependent conductivity hysteresis is important for the fundamental understanding of the interplay between the ferroelectric polarization and charge carriers in graphene. It is also important for practical memory applications because this hysteresis emulates the operation of nonvolatile memories and reveals the range of ON and OFF currents that can be achieved in long term data storage. It is demonstrated that this measurement scheme can be used to optimize the memory performance of graphene-PZT FeFETs that can exhibit nonvolatile time-independent ON/OFF ratios of over 5. The described measurement technique can potentially be used in the studies of kinetics of charge trap dissipation, polarization-dependent properties, and memory performance of FeFET devices comprising other 2D materials and various ferroelectric substrates.