Solid-state memory of ferroelectric tunnel junctions based on distorted ReS2

Abstract

Ferroelectric with quantum-mechanical tunnel allows non-volatile resistance states and fast readout of the tunnel current in the ferroelectric tunnel junctions (FTJs) through the influence of ferroic orders. However, the complex interfacial effect between electrodes and traditional ferroelectric films has still remained to be solved. When 2D ferroelectrics are used in FTJs, the lattice-matched constraint and intermixing of cations between ferroelectric and substrate electrode can be avoid. Here we show various FTJs with low energy consuming, and high endurance made from 2D ferroelectric ReS2 and different electrodes such as Pt/ReS2/Au, W/ReS2/SiO2/Si and W/ReS2/Nb:STO. With the help of in situ atomic force microscopy and piezoresponse force microscopy, we show that the memory can be manipulated in less than 1 μm2 and the resistance switching should be caused by the ferroelectric polarization direction in the distorted ReS2. Then, we demonstrate that the memory devices can be easily transferred to a polyimide or flexible SiO2/Si substrate. These FTJs shows good bending stability, illustrating their potential applications in flexible electronics. Considering the weak Van der Waals interfacial bonding between 2D ferroelectric and electrode, the polarization-dependent Schottky emission and interface-limited Fowler-Nordheim tunnel current play the key role in resistance switching respectively. Our work provides a simple way to construct various building blocks for circuits in harsh electronics with low energy consuming, good bending stability and high-density data storage.