Photovoltaic effect in BiFeO3/BaTiO3 multilayer structure fabricated by chemical solution deposition technique

• Bismuth ferrite and barium titanate multilayered thin films were deposited on Pt/Ti/SiO2/Si substrates using CSD technique.
• Photovoltaic response characteristics were studied in MFM capacitor configuration (Au/BFO/BTO/BFO/BTO/Pt).
• Efficient separation of photogenerated charge carriers due to depolarization field leads to high photovoltaic response.
• High depolarization field was due to higher remnant polarization and interfacial strain between BFO and BTO layers.
• Prepared multilayers exhibits enhanced photovoltaic response indicating realization of efficient multifunctional structure.

Photovoltaic (PV) properties of bismuth ferrite (BFO) and barium titanate (BTO) multilayered ferroelectric BFO/BTO/BFO/BTO thin film structure deposited on Pt/Ti/SiO2/Si substrates using chemical solution deposition technique are presented. X-ray diffraction analysis confirms pure phase polycrystalline nature of deposited perovskite multilayered structures. Simultaneously both distorted rhombohedral (R3c) and tetragonal phases (P4mm) of the respective BFO and BTO components are also well retained. The ferroelectric sandwiched structures grown on fused quartz substrates exhibit high optical transmittance (~70%) with an energy band gap 2.62 eV. Current–voltage characteristics and PV response of multilayered structures is determined in metal-ferroelectric-metal (MFM) capacitor configuration. Considerably low magnitude of dark current density 1.53×10−7 A at applied bias of 5 V establish the resistive nature of semi-transparent multilayered structure. Enhanced PV response with 40 nm thin semitransparent Au as top electrode is observed under solid-state violet laser illumination (λ – 405 nm, 160 mW/cm2). The short circuit current density and open circuit voltage are measured to be 12.65 µA/cm2 and 1.43 V respectively with a high retentivity. The results obtained are highly encouraging for employing artificial multilayered engineering to improve PV characteristics.

Figure optionsDownload as PowerPoint slide