  A transition in source-drain current vs back gate voltage ID - VBG
characteristics from extrinsic polar molecule dominant hysteresis to
anti-hysteresis induced by an oxygen deficient surface layer that is intrinsic
to the ferroelectric thin films has been observed on graphene field-effect
transistors on Pb0.92La0.08Zr0.52Ti0.48O3 gates GFET/PLZT-Gate during a vacuum
annealing process developed to systematically remove the polar molecules
adsorbed on the GFET channel surface. This allows detangle of the extrinsic and
intrinsic hysteresis on GFET/PLZT-gate devices and detection of the dynamic
switch of electric dipoles using GFETs, taking advantage of their high gating
efficiency on ferroelectric gate. A model of the charge trapping and pinning
mechanism is proposed to successfully explain the transition. In response to
pulsed VBG trains of positive, negative, as well as alternating polarities,
respectively, the source-drain current ID variation is instantaneous with the
response amplitude following the ID - VBG loops measured by DC VBG with
consideration of the remnant polarization after a given VBG pulse when the gate
electric field exceeds the coercive field of the PLZT. A detection sensitivity
of around 212 dipole/um2 has been demonstrated at room temperature, suggesting
the GFET/ferroelectric-gate devices provide a promising high-sensitivity scheme
for uncooled detection of electrical dipole dynamic switch.
