Nanoscale Mapping of Carrier Distribution Regulated by Polarization in 2D FeFETs.

The emergence of 2D ferroelectrics, sliding ferroelectrics, and 2D ferroelectric semiconductors has greatly expanded the potential applications of two-dimensional ferroelectric field-effect transistors (2D FeFETs) in nonvolatile memory, neuromorphic synapses, and negative capacitance. However, the interaction between ferroelectric and semiconductor layers remains not well understood, and characterization methods to correlate carriers and polarization dynamics at the nanoscale are still lacking. Utilizing in situ scanning microwave impedance microscopy and piezoresponse force microscopy measurements, we employed a Pb(ZrTi)O/MoS-based 2D FeFET as an example to reveal, with high spatial resolution, the microscopic redistribution of carriers. This study uncovers the microscopic behavior of ferroelectric-semiconductor heterojunctions, paving the way for a deeper understanding of ferroelectric-gating effects and retention issues at the nanoscale in 2D FeFETs.