Chi-Shun Tu, Cheng-Sao Chen, Pin-Yi Chen, Hsiu-Hsuan Wei, V.H. Schmidt, Chun-Yen Lin, J. Anthoniappen, Jenn-Min Lee
This work reports enhanced photovoltaic (PV) responses of (Bi1 - xSmx)FeO3 (x = 0.0, 0.05, 0.10) ceramics (BFO100xSm) with ITO film under near-ultraviolet irradiation (λ = 405 nm). The ceramics were characterized by micro-Raman scattering, high-resolution transmission electron microscopy, and synchrotron X-ray absorption spectroscopy (XAS). A rhombohedral R3c symmetry with tilted FeO6 octahedra has been confirmed. The Fe K-edge absorption spectra reveal a slight shift toward higher energy as A-site Sm3+ substitution increases. The oxygen K-edge XAS reveals an enhancement of hybridization between the O 2p and unoccupied Fe 3d states due to Sm doping. The optical band gaps are in the range of 2.15-2.24 eV. The maximal PV power-conversion and external quantum efficiencies respectively reach 0.37% and 4.1% in the ITO/BFO5Sm/Au heterostructure. The PV responses can be described quantitatively by a p-n-junction-like model. The domain structures and hybridization between the O 2p and Fe 3d states play important roles for the PV responses. © 2015 Elsevier Ltd.
Department of Physics, Fu Jen Catholic University, New Taipei City, 24205, Taiwan; Department of Mechanical Engineering, Hwa Hsia University of Technology, New Taipei City, 23567, Taiwan; Department of Mechanical Engineering, Ming Chi University of Technology, New Taipei City, 24301, Taiwan; Department of Physics, Montana State University, Bozeman, 59717, MT, United States; Department of Physics, University of San Carlos, Cebu, 6000, Philippines; National Synchrotron Radiation Research Center, Hsinchu, 30076, Taiwan
