Temperature dependent charge transport in graphene with ferroelectric gating

CVD graphene was electrically characterized in a field effect transistor configuration with ferroelectric (FE) gating in the temperature range 300K < T < 350K. Saturated hysteresis loops of the FE co-polymer poly(vinylidene fluoride-trifluoroethylene)-PVDF-TrFE(75/25) showed that the memory window width decreased as temperature increased. Device trans-conductance (I-Vg) curves exhibit hysteresis behavior with two charge neutrality points (CNP) corresponding to the up/down polarization of the ferroelectric gate. Increasing the temperature decreased the change of the gate voltage and increased the change in the channel current measured between the two CNP’s. The electron mobility showed a steeper decrease compared to the hole mobility as temperature was increased. Desorption of O₂ and H₂O was used to explain these observations. Finally, non-volatile switching was realized using the charge storage property of the gate insulator.