A Gate Programmable van der Waals Metal‐Ferroelectric‐Semiconductor Vertical Heterojunction Memory

Abstract

Ferroelectricity, one of the keys to realize non‐volatile memories owing to the remanent electric polarization, is an emerging phenomenon in the 2D limit. Yet the demonstrations of van der Waals (vdW) memories using 2D ferroelectric materials as an ingredient are very limited. Especially, gate‐tunable ferroelectric vdW memristive device, which holds promises in future multi‐bit data storage applications, remains challenging. Here, a gate‐programmable multi‐state memory is shown by vertically assembling graphite, CuInP2S6, and MoS2 layers into a metal(M)‐ferroelectric(FE)‐semiconductor(S) architecture. The resulted devices seamlessly integrate the functionality of both FE‐memristor (with ON–OFF ratios exceeding 105 and long‐term retention) and metal‐oxide‐semiconductor field effect transistor (MOS‐FET). Thus, it yields a prototype of gate tunable giant electroresistance with multi‐levelled ON‐states in the FE‐memristor in the vertical vdW assembly. First‐principles calculations further reveal that such behaviors originate from the specific band alignment between the FE‐S interface. Our findings pave the way for the engineering of ferroelectricity‐mediated memories in future implementations of 2D nanoelectronics.

Enhanced electrodynamic gating in two-dimensional transistors using ferroelectric capping

“…Moreover, the hysteresis-induced distinct on/off ratio between the low and high resistance states (e.g., ∼10 5 in this work) can be beneficial for nonvolatile resistive random-access memory (ReRAM) applications. In contrast to the understanding of ferroelectric and negative capacitance FET [18,19,[24][25][26][27] and ReRAM [28][29][30][31] devices, further exploration about the hysteresis in the ferroelectric capping structure is needed, such as its dependence on the sweep range, sweep rate, capacitance matching, and prototype demonstrations.…”

Recent Advances in Layered Two‐Dimensional Ferroelectrics from Material to Device

“…Second, the computational cost is low since a variety of naturally physical systems can be used as the reservoir. [107] In addition to 𝛼-In 2 Se 3 , synaptic devices based on other 2D ferroelectrics such as CIPS, [108][109][110] SnS [56,111] and SnSe [112] have also been demonstrated.…”

Cu+ Migration and Resultant Tunable Rectification in CuInP2S6

“…The bloom of various van der Waals (vdW) materials has stimulated enthusiasm for their application in devices, such as vdW-based p–n junctions, memristors, sensors, field effect transistors, and actuators, − which have great potential in modern information technology and neuromorphic computing. Among the candidate materials, ferroelectric materials are rare, especially toward the few-layer thickness limit.…”