Role of Defects and Power Dissipation on Ferroelectric Memristive Switching

Abstract

Advancement of information technology requires low power, high speed, and large capacity non-volatile memory. Memristors have potential applications for not only information storage but also neuromorphic computation. Memristive devices are mostly focused on the use of binary oxides as the resistive switching materials. On the other hand, polarization assisted memristive devices based on ternary ferroelectric oxides are attracting more attention due to their unique switching properties. However, the underlying switching mechanisms and the current–voltage rotation direction are still not fully understood yet. By comparing stoichiometric BaTiO3, BiFeO3, and Bi1-xFeO3-δ ferroelectric memristors with different cation stoichiometry, it is found that off-stoichiometry-induced traps can play a critical role in controlling the ferroelectric memristive switching behavior. Ferroelectrics with slight off-stoichiometry show greatly enhanced switching properties, and the switching on/off ratio is mainly determined by the trap energy levels and concentrations. The rotation direction of current–voltage hysteresis loop is affected by the defects, which can be controlled by synthesis and power dissipation. These findings provide insight in understanding the role of defects in ferroelectric memristors and offer guidance to design ferroelectric memristors with enhanced performance.