Hydrothermal growth of nitrogen-doped ZnO crystals was performed in alkaline solutions with the addition of 1 N LiNO3 at T-dissoultion/T-growth = 365 degrees C/350 degrees C, and in a 20% NH4OH solution at 490 degrees C/475 degrees C, respectively. An average nitrogen concentration of approximately 10(18) at atom/cm(3) was incorporated in the crystals. X-ray diffraction showed that the crystals grown from the 1 M LiNO3 solution are of high quality, exhibiting high resistivity. The spontaneously nucleated crystals were obtained from the NH40H solution; a weak peak at 3.236 eV and a peak at 3.332 eV of photoluminescence were found at 18 K from these crystals after annealing at 600 degrees C for 2h. The emission peaks correspond to the nitrogen-associated donor-acceptor pair (DAP) and electron-acceptor emissions in ZnO:N prepared by other techniques reported in the literature. (c) 2005 Elsevier B.V. All rights reserved.