Eu-doped ZnO nanorods (NRs) emitting several discrete lines in the visible spectrum were synthesized on silicon (100) substrates using a hydrothermal process. Structural investigations by transmission electron microscopy and X-ray diffraction showed that Eu atoms had been incorporated into the ZnO lattice without forming Eu-related alloys. The photoluminescence (PL) spectra showed discrete emission peaks from the 4% Eu-doped ZnO NRs, indicating that the doped Eu3+ ions in the ZnO NRs act luminescence centers. The PL intensity of specific emission peaks from the Eu-doped ZnO NRs increased after post thermal annealing at 500 degrees C assumed to be due to the annihilation of point defects in the ZnO crystal lattice. (C) 2013 Elsevier B.V. All rights reserved.