Dual Modulation of Barrier Width and Height in van der Waals Ferroelectric Tunnel Junctions.

Two-dimensional ferroelectric tunnel junctions (2D FTJs) have attracted extensive attention in recent years, which mainly change the height of the tunnel barrier via manipulation of the ferroelectric polarization. However, it is very challenging to realize the high tunneling electroresistance (TER) of FTJs based on the barrier height. Here, we report the 2D FTJs using a unique structure with semiconducting MoS/α-InSe/monolayer graphene, where ferroelectric polarization of α-InSe shifts the barrier height by 1.05 eV. More importantly, the MoS dynamically tunes the barrier width, overcoming traditional barrier height limitations and enhancing TER by an order of magnitude. The dual modulation of barrier width and height yields a giant TER of more than 1 × 10 at room temperature. In addition, the FTJs possess excellent retention time for up to 10 years. This study exhibits that the constructed 2D FTJs have unprecedented applications in achieving high-performance memory, electronic, optoelectronic, and neuromorphic computing devices.