Effect of Nd and Mn Co-Doping on Dielectric, Ferroelectric and Photovoltaic Properties of BiFeO₃

Bi1−xNdxFe0.99Mn0.01O3 (BNFMO, x = 0.00~0.20) films were epitaxially grown on Nb:SrTiO3 (001) substrates using pulsed laser deposition. It was found that the Nd-doping concentration has a great impact on the surface morphology, crystal structure, and electrical properties. BNFMO thin film with low Nd-doping concentration (≤16%) crystallizes into a rhombohedral structure, while the high Nd-doping (>16%) will lead to the formation of an orthogonal structure. Furthermore, to eliminate the resistive switching (RS) effect, a positive-up–negative-down (PUND) measurement was applied on two devices in series. The remnant polarization experiences an increase with the Nd-doping concentration increasing to 16%, then drops down with the further increased concentration of Nd. Finally, the ferroelectric photovoltaic effect is also regulated by the ferroelectric polarization, and the maximum photocurrent of 1758 μA/cm2 was obtained in Bi0.84Nd0.16Fe0.99Mn0.01O3 thin film. BNFMO films show great potential for ferroelectric and photovoltaic applications.