Films of Eu-doped GaN (GaN:Eu) were grown on c-plane of sapphire (c-Al(2)O(3)), GaAs(100), Si(100) and glass substrates by RF magnetron sputtering method. The X-ray diffraction (XRD) measurement of the sputtered film was carried out. For GaN:Eu and undoped GaN, the lattice constants c and a of as-grown films were larger than those of the bulk GaN. After annealing, the lattice constants c and a of the films decreased. (c) 2008 Published by Elsevier B.V.