Photovoltaic Effect in ITO/rGO/BFO/Au Heterostructures

Abstract

Multiferroic BiFeO3 (BFO) thin films showed promising potential towards photovoltaic applications due to its superior ferroelectric properties and optical bandgap lies in the visible region. Among other wide bandgap ferroelectric photovoltaic (Fe-PV) materials (i.e. BaTiO3, LiNbO3 and Pb(Zr,Ti)O3), BFO exhibits large open circuit voltage (VOC), tunable output, and switchable photovoltaic effect. Herein, we report a novel heterostructure based photovoltaic cells by integrating a carbon material as semiconducting interlayer between bottom metal electrode and BFO thin film. Thin film heterostructures of In2O3-Sn2O3 (ITO)/reduced graphene oxide (rGO)/BFO/Au in metal/semiconductor/ferroelectric/metal stack were fabricated to study their photovoltaic properties, where BFO films were deposited by pulsed laser deposition technique on N+-type reduced rGO coated conducting ITO substrate. As grown ITO/rGO/BFO/Au heterostructures showed a reasonably improved photovoltaic response with short-circuit current density of ~86 µA/cm2. We believe that two built-in fields generated at Au/BFO and BFO/rGO interfaces are responsible for separation and transport of photo-excited electron-hole pairs which can cause improved photocurrent response in these thin film heterostructures.