Growth of ZnO films was carried out on the c-plane sapphire (alpha -Al2O3 (0 0 0 1)) and glass substrates by metalorganic molecular beam epitaxy (MOMBE) using diethylzinc (DEZn) and H2O as source precursors. The lattice constant c of the ZnO/alpha-Al2O3 (0 0 0 1) layer decreased with increasing feeding ratio of H2O to DEZn (VI/II ratio). Photouminescence (PL) intensity ratio of the green band to the near-band-edge (NBE) emission (I-GB/I-NBE) became smaller with increasing VI/II ratio. These results are probably due to the decrease in oxygen vacancy concentration. Highly c-axis-oriented polycrystalline ZnO films were grown at T-S >= 300 degrees C under VI/II = 25. The full-width at half-maximum (FWHM) value of the (002) diffraction peak was minimum at T-S = 300-375 degrees C. The I-GB/I-NBE ratio for the polycrystalline ZnO/glass film showed minimum value at T-S = 300 degrees C. The quality of the ZnO/glass film was best at T-S = 300-375 degrees C, which is lower in comparison with the ZnO/alpha-Al2O3 (0 0 0 1) layer. (c) 2006 Elsevier B.V. All rights reserved.