High-Performance Photovoltaic Readable Ferroelectric Nonvolatile Memory Based on La-Doped BiFeO3 Films.

Epitaxial La0.1Bi0.9FeO3 (LBFO) films with SrRuO3 (SRO) bottom electrodes were fabricated on SrTiO3(001) substrates by magnetron sputtering. The LBFO thin films exhibit strong ferroelectric properties. Nonvolatile reversible resistance switchings and switchable photovoltaic effects controlled by electric field have been observed in Pt/LBFO/SRO heterostructures. With the optimized LBFO film thickness, the observed room temperature pulsed-read resistance switching ratio can reach 105% magnitude by applying ±2.7 V pulse voltages. Besides, the observed ferroelectric switchable photovoltaic effect in the visible wavelength range shows a large tunable open-circuit photovoltage from -75 to -330 mV. The switching mechanisms in resistance and photovoltaic effects are demonstrated to be directly related to the ferroelectric reversal, which can be attributed to the polarization-modulated interfacial barriers and deep trap states.