Undoped and Zn-doped GaN nanowires were synthesized by chemical vapor deposition (CVD), and the effects of substrates, catalysts and precursors were studied. A high density of GaN nanowires was obtained. The diameter of GaN nanowires ranged from 20 nm to several hundreds of nm, and their length was about several tens of pm. The growth mechanism of GaN nanowires was discussed using a vapor-liquid-solid (VLS) model. Furthermore, room-temperature cathodoluminescence spectra of undoped and Zn-doped GaN nanowires showed emission peaks at 364 and 420 nm, respectively. (C) 2009 Published by Elsevier B.V.