Bulk photovoltaic effects in Mn-doped BiFeO_3 thin films and the optical strains

摘要

Pt/1-mu m-thick Bi1.0Fe0.99Mn0.01O3 (BFMO)/Pt coplanar capacitors with an interelectrode distance of 260 mu m have been fabricated on vicinal SrTiO3 (STO) (001) substrates by radio frequency magnetron sputtering. The bulk photovoltaic effect of a BFMO thin film has been investigated by measuring the current-voltage (I-V) characteristics of the Pt/BFMO/Pt coplanar capacitors under blue-violet laser illumination (lambda = 405 nm). The I-V characteristics show the light-polarization-dependent open-circuit voltage (V-OC) with a maximum of -209V. In addition, the optical strain of a BFMO/STO cantilever with a size of 15 mm x 1.3mm x 70 mu m has been investigated by measuring the displacement of the edge of the cantilever under blue-violet laser illumination. The edge displacement depended on light polarization, indicating that the optical strain is due to the coupling between the bulk photovoltaic effect and the inverse piezoelectric effect. (C) 2018 The Japan Society of Applied Physics