Effect of Poling on Photovoltaic Properties in Highly Oriented BiFeO 3 Thin Films.

We report enhancement of photovoltaic properties of highly oriented BiFeO3(BFO) thin films. The single phase rhombohedral R3c space group structure was confirmed by XRD and Raman spectra in the films grown on SrTiO3(111) substrates using RF magnetron sputtering. The films of BFO were characterized in planar geometry with top Pt electrodes having 200μm diameter, ∼40nm thickness and at a regular spacing of ∼150μm deposited by DC sputtering process. For photovoltaic studies the current voltage characteristic of as grown and poled samples were studied under the white light illumination having energy density of ∼1kW/m2. The as grown films showed open circuit voltage (Voc) of ∼3.9V which increased up to ∼17.8V on poling with 200V. This enhancement in Voc by poling was attributed to increase in net polarization due to alignment of domains in the direction of applied electric field and hence potential barriers between the domains. [ABSTRACT FROM AUTHOR]