Blázquez Martínez A., Mandal B., Glinsek S., Granzow T.
Acta Materialia, vol. 283, art. no. 120481, 2025
Bismuth ferrite (BiFeO<sub>3</sub>) is an attractive multiferroic material, extensively explored in photoferroelectric investigations. However, its applications are hindered by the high leakage current, requiring precise control of charge transport properties. Defect engineering has emerged as a promising strategy to address this issue: controlling the defect chemistry, particularly oxygen vacancies, is key to tuning the electrical properties. This study investigates the influence of 5% [Formula presented] - and 2% [Formula presented] -doping on the dark and light-induced charge transport properties of polycrystalline BiFeO<sub>3</sub> films. Our results demonstrate that [Formula presented] reduces dark conductivity by decreasing oxygen vacancy concentration with no change in the physical nature of the charge transport mechanism. In contrast, [Formula presented] modifies the charge transport mechanism, increasing low-field (E < 100 kVcm<sup>-1</sup>) dark conductivity while drastically reducing high-field (E > 250 kVcm<sup>-1</sup>) dark conductivity. This tuning of the defect chemistry is also key to enhance the photovoltages of the bulk photovoltaic effect in BiFeO<sub>3</sub>. High photoinduced electric fields up to 7 kVcm<sup>-1</sup> and low photoconductivity values are obtained with [Formula presented] -doping, while high short-circuit photocurrent values are obtained with [Formula presented] -doping.
