Well-aligned Y-doped ZnO (YZO) nanorod arrays were synthesized on YZO-seeded quartz glass substrates by hydrothermal method. The diameter and the density of the YZO nanorods were effectively controlled by modifying the grain morphology of the seed layer. The microstructures of the seed grains were manipulated by vacuum annealing (300-800 degrees C), and the texture of the seed grains significantly affected the physical properties of the YZO nanorods. From analyses of microstructural and optical properties of the YZO nanorods, the size and the density of the YZO nanorods were observed to strongly depend on those of the seed grains that could be controlled by annealing temperatures. The simple and scalable method proposed here could be beneficial for the controllable growth of vertically-aligned YZO nanorod arrays and their nano-device fabrications. (C) 2015 Elsevier B.V. All rights reserved.