ZnO epitaxial layers were successfully grown on nitridated Si(1 0 0) substrate with high-temperature (HT) GaN and low-temperature ZnO double buffer layers by molecular beam epitaxy. It was found that the HT-GaN buffer was crystalline with both hexagonal and cubic phases. It was also found that numerous cone-shaped nano-islands were formed on the ZnO epitaxial layers with density, average diameter and average height of 1.25 x 10(9) cm(-2), 300 nm and 150 nm, respectively. X-ray diffraction and photoluminescence results both indicate that quality of our ZnO epitaxial layers was good. (C) 2007 Elsevier B.V. All rights reserved.