Photovoltaic effect of ITO/Bi_3.15Nd_0.85Ti₃O₁₂/Pt heterojunction structure

ITO/BNT/Pt heterojunction structure has been prepared by sol-gel method combined with dc magnetron sputtering. The BNT (Bi_3.15Nd_0.85Ti₃O₁₂) films were polycrystalline with typical ferroelectric hysteresis. The ITO/BNT/Pt structure displayed photovoltaic properties with a V_oc of about 0.28 V and a photocurrent of 2.4 nA. After being polarized by a + 4 V pulse, at the voltage of 0.1 V, the current was 3 × 10⁻⁸ A, while it was −1 × 10⁻⁹ A after being polarized by a −4 V pulse. This demonstrated the depolarization field of the BNT films played a significant role in the I–V properties of the ITO/BNT/Pt structure. Therefore, we speculated the depolarization field had influenced the photovoltaic properties.