Flexoelectricity-Enabled Modulation of Fermi Level in Graphene/PZT Heterostructure for Weak Pressure Signals Sensor

The flexoelectricity polarization of nanoscale dimensions has a natural advantage in realizing highly sensitive pressure sensors in 2-D. Furthermore, as typical 2-D material materials, graphene was often combined for pressure sensors. As the result of a high dielectric constant, Pb(Zr
$_{{0}.{52}}$
Ti0.48)O3(PZT) nanofilm could produce large surface polarization potential when subjected to external weak force. Then, fermi-level graphene on the surface of PZT film can be regulated by polarization electric field, which weak pressure signals’ sensor. We report on a novel graphene-based PZT pressure sensor with high sensitivity, fast response time, and weak pressure signals based on the flexoelectricity enhancement effect. The simulation of the graphene/PZT composite structure by COMSOL multiphysics and MATLAB indicates that the strain gradient of the PZT film is as high as
$10^{{5}}$
. Combining the high flexoelectricity coeffcient of PZT with outstanding carrier transport of graphene, graphene-based PZT pressure sensor except high sensor expects exhibition highly sensitive, with an average sensitivity of 0.01 kPa
$^{-{1}}$
, a faster response time as 0.06 s, and signal to noise ratio (SNR) is 61.9 dB in the range of pressure from 0.098 to 9.8 kPa. When compared with conventional pressure sensors, the sensors have orders of magnitude higher sensitivity. This graphene/PZT-based pressure sensor will have great potentials for highly sensitive weak pressure signal detection.