Photovoltaic property of sputtered BiFeO3 thin films

Photovoltaic (PV) property of sputter-deposited BiFeO3 (BFO) polycrystalline films on Pt/Ti/SiO2/Si(1 0 0) substrates has been studied. Isotropic single phase perovskite BFO is obtained in the growth temperature (Tg) range of 350-450 °C. The increase of Tg and film thickness promote grain growth resulting in roughened surface. Significant PV effect under laser illumination with wavelength of 405 nm is obtained. Short-circuit photocurrent density (Jsc) increases with the increase of laser intensity (I). The Jsc at I = 220 mW/cm2 (Jmax) are increased with the increase of the growth temperature and BFO thickness. The correlation between Jmax and the size of coherent scattering domain indicates that PV property is highly related to the structural defects. Furthermore, PV effect is reduced at higher Tg = 500 °C or for larger t = 400 nm due to the appearance of the impurity phase and rougher surface.