Homoepitaxy of rhombohedral-stacked MoS2 with room temperature switchable ferroelectricity

TL;DR

This paper demonstrates room-temperature switchable ferroelectricity in homoepitaxial MoS2 with 3R stacking domains, enabling potential ultrathin memory devices through controlled synthesis and domain engineering.

Contribution

It introduces a method to grow MoS2 homoepitaxial patterns with 3R polytypic domains that exhibit ferroelectric switching at room temperature, a significant advancement over natural crystals.

Findings

MoS2 homoepitaxial patterns with 3R domains show ferroelectric switching.

Switchable ferroelectricity observed at room temperature in these patterns.

Memory window exceeds that of compact 3R bilayer devices.

Abstract

The discovery of interfacial ferroelectricity in two-dimensional rhombohedral (3R)-stacked semiconductors opens up a new pathway for achieving ultrathin computing-in-memory devices. However, exploring ferroelectricity switching in natural 3R crystals is difficult due to lack of co-existing 3R stacking domains. Here, we present that MoS2 homoepitaxial patterns with 3R polytypic domains can manifest switchable ferroelectricity at room-temperature. Based on the diffusion limited aggregation theory, such MoS2 patterns are formed under the low Mo chemical potential and low temperature with respect to common chemical vapor deposition synthesis. The alternation of 3R polytypes in the MoS2 homoepitaxial patterns, observed by scanning transmission electron microscopy, accounts for ferroelectricity switching. The MoS2 field-effect transistors with 3R polytypic domains exhibit a repeatable counterclockwise hysteresis with gate voltage sweeping, an indication of ferroelectricity switching, and the memory window exceeds those measured for compact-shaped 3R bilayer devices. This work provides a direct growth concept for layered 3R-based ferroelectric memory.