Photovoltaic Properties of Multiferroic BiFeO3/BiCrO3 Heterostructures

We report a power conversion efficiency of similar to 0.01% in multistacking of BiFeO3/BiCrO3 bilayer thin films used as active layers in a photovoltaic (PV) device. The films were epitaxially deposited by pulse laser deposition onto (100) oriented CaRuO3-coated LaAlO3 substrates and were subsequently illuminated with 1 sun (AM 1.5). The fill factor is determined to be 0.31%, a remarkable value for ferroelectric- and multiferroic-based PV devices. Our results demonstrate that photocurrent density and photovoltage can be tuned by varying the thickness and number of respective bilayers in the improvement of PV properties of multiferroic heterostructures. The maximum photocurrent is generated at an optimal multilayer thickness of 60nm, with its origin being mainly ascribed to the contribution of ferroelectric polarization.