Deterministic Linear Modulation of Multistate Conductance of 2D/Ferroelectric Heterojunction Through the Controlled Nucleation

ABSTRACT 2D semiconductor/ferroelectric heterojunctions are promising for in‐memory neuromorphic computing, though the inherently nonlinear switching dynamics of ferroelectrics impose serious challenges, leading to undesirable nonlinearity in their voltage‐pulse‐modulated multistate conductance. In this work, we propose an effective strategy to overcome such difficulty, taking advantage of the electric field concentration underneath conductor‐semiconductor interface that promotes controlled instead of random nucleation. As a result, a domain dynamics fundamentally different from Kolmogorov‐Avrami‐Ishibashi (KAI) switching model emerges, leading to linear modulations of ferroelectric domain, charge carrier concentration, and conductance in MoS 2 /Pb(Zr,Ti)O 3 (PZT) heterojunction via voltage pulses, as demonstrated by comprehensive piezoresponse force microscopy (PFM) and scanning microwave impedance microscopy (sMIM) studies. The domains can be reversibly written and erased via forward and backward switching in a linear manner, and the heterojunction also enjoys good endurance and robust retention, highlighting its promises for synaptic device applications. Our work thus overcomes a major obstacle for ferroelectric synaptic devices, paving the way for the application of 2D/ferroelectric heterojunctions in neuromorphic computing.