Mechanism of Polarization Fatigue in BiFeO3: the Role of Schottky Barrier

TL;DR

This study investigates how charge injection at interfaces causes polarization fatigue in BiFeO3 capacitors, highlighting the importance of Schottky barriers and electrode materials in improving device longevity.

Contribution

It reveals the critical role of Schottky barriers in charge injection and fatigue, and demonstrates how electrode choice influences device durability.

Findings

Charge injection causes domain pinning and fatigue.

Lowering Schottky barrier improves fatigue resistance.

Electrode material affects polarization stability.

Abstract

By using piezoelectric force microscopy and scanning Kelvin probe microscopy, we have investigated the domain evolution and space charge distribution in planar BiFeO3 capacitors with different electrodes. It is observed that charge injection at the film/electrode interface leads to domain pinning and polarization fatigue in BiFeO3. Furthermore, the Schottky barrier at the interface is crucial for the charge injection process. Lowering the Schottky barrier by using low work function metals as the electrodes can also improve the fatigue property of the device, similar to what oxide electrodes can achieve.