Leakage Current and Photovoltaic Properties in a Bi₂Fe₄O₉/Si Heterostructure

A heterostructure composed of a Bi₂Fe₄O₉ film and an n−type Si substrate is fabricated. The characteristics of leakage current density versus electric field are investigated and the leakage current density is about 6×10⁻⁶ A/cm² at an electric field of 200 kV/cm at 300 K. A strong photovoltaic effect is observed when the heterostructure is exposed to a laser pulse with a wavelength of 532 nm and a power of 6 mW/mm². It is found that the peak photovoltages initially increase with decreasing temperature, followed by a decrease at T<210 K. These results reveal that the heterostructure is a promising candidate for photovoltaic devices that are compatible with Si integrated circuits.