Well-aligned zinc oxide (ZnO) nanorods were densely grown on Si substrate using ZnO thin-film seed layer without any catalysts and/ or additives by a simple solid-vapour phase thermal sublimation technique. The growth mechanism can be interpreted as self-catalyst of zinc particles based on vapour-solid (VS) mechanism. High-resolution transmission electron microscopy (HRTEM) image and selected area electron diffraction (SAED) pattern confirmed that the single-crystalline growth of the nanorods were preferentially along c-axis of hexagonal crystal system. High-crystal quality ZnO nanorods with strong near band edge emission centred at 380 nm can be achieved on Si substrate by the introduction of sufficient oxygen during the nanorod growth processing. (c) 2007 NIMS and Elsevier Ltd. All rights reserved.