Erbium-doped BaF2 nanoparticles were prepared using the ultrasonic surge method. The particles were characterized by X-ray diffraction, transmission electron microscope, photoluminescence and absorption. The results show that when Er3+ ions were introduced into the BaF2 lattice, cubic fluorite-type Ba(1-x)Ef(x)F(2+x) solid solution, x = 0.42 was formed. Furthermore, the crystalline phase of Ba1-xErxF2+x solid solution was largely influenced by the annealing temperature. (C) 2013 Elsevier B.V. All rights reserved.