Photovoltaic phenomena in BiFeO3 multiferroic ceramics

Open-circuit photovoltage and short-circuit photocurrent were investigated in BiFeO3 (BFO) ceramics as functions of laser wavelength (lambda = 373 and 532 nm), illumination intensity, and sample thickness. BFO ceramics exhibit significant photovoltaic responses under near-ultraviolet illumination of lambda = 373 nm. The photovoltaic responses strongly depend on wavelength, light intensity, and sample thickness. The relation between photovoltaic responses and light intensity can be described by exponential equations, E-OC = E-S[1 - exp(-I/alpha)] and J(SC) = J(S)[1 - exp(-I/beta)]. E-OC, J(SC), E-S, and J(S) are open-circuit photovoltage (V/cm), short-circuit photocurrent density (A/cm(2)), saturated photovoltage (V/cm), and saturated photocurrent density, respectively. This work suggests that BFO ceramic exhibits stronger photovoltaic responses than the ferroelectric WO3-doped Pb1-xLax(ZryTiz)(1-x/4)O-3 ceramics and Pb(Mg1/3Nb2/3)(1-x)TixO3 crystals. (C) 2012 American Institute of Physics. [doi:10.1063/1.3675984]