Ferroelectric Polarization Effects on the Transport Properties of Graphene/PMN-PT Field Effect Transistors

Single-layer graphene was transferred onto (1 – x)[Pb(Mg1/3Nb2/3)O3]–x[PbTiO3]0.3 (PMN-PT) substrate to investigate the transport properties of graphene-based field effect transistors (FETs) by ferroelectric gating. The graphene/PMN-PT FET exhibited p-type characteristics with a large memory window and an on/off current ratio of about 5.5 in air ambient conditions at room temperature. By prepoling the PMN-PT substrate, the FET showed a reduction in p-doping for the graphene/PMN-PT FET, implying the pre-polarization and the polarization reversal played an important part in the behaviors of graphene on PMN-PT. The observation of simultaneous rise in gate current with the dramatic transition in drain current suggested that the transport properties of graphene mainly stemmed from the coupling of the ferroelectric polarization to the charge carriers in graphene. The field effect mobility and the excess hole concentration were calculated to be about 4.52 × 103 cm2 V–1 s–1 and 6.74 × 1012 cm–2, respectively. Furthermore, the sheet resistance showed high dependence on temperature and gate voltage, indicating metallic behaviors of graphene on PMN-PT. Additionally, the sheet resistance of graphene on the PMN-PT was much smaller than that on SiO2.