Influence of rare-earth elements doping on structure and optical properties of BiFeO_3 thin films fabricated by pulsed laser deposition

摘要

The Bi_(1-x)Eu_xFeO_3 (BEFO_x, x=0,0.03, 0.05, 0.07, 0.1) films were grown on LaNiO_3 coating Si substrates by pulsed laser deposition. X-ray diffraction patterns indicate that the films exhibit a (100)-highly oriented pseudocubic perovskite crystal structure. Scanning electron microscopy exhibits that the number of island-like structures decreases with increasing Eu dopant. The position of the A_1-1 mode of the films in the Raman spectra shifts to higher wavenumber with increasing x. With increasing the amount of Eu, the refractive index increases and the extinction coefficient decreases. In addition, the band gap of BEFO_x films decreases with increasing Eu dopant.