ZnO nanorod arrays were effectively selective-grown on a p-type GaN:Mg layer through chemical bath deposition (CBD) at a low temperature hydrothermal synthesis (85 degrees C) with a ZnO seed layer. The 5 mu m-diameter hole-array patterns of the ZnO seed layer were grown on a p-type GaN:Mg layer in aqueous solution with a mercury lamp illumination. The diameter and the height of ZnO nanorods were measured as the values of 500 nm and 3 mu m, respectively. The growth orientation, surface morphology, and aspect ratio of the ZnO nanorods can be controlled and formed on the hole-array patterned ZnO seed layer. The peak wavelength of the photoluminescence spectrum was measured at 384 nm. (C) 2010 Elsevier B.V. All rights reserved.